There are those known as Takeshi who have fought since ancient times to protect people. Some of them have even dared to become Oni, to fight against the evil Makamou. Following the Oni are the boys and girls who start toward tomorrow, step by step�

After rescuing Chizu, Hibiki spends the night at the memorial where Asumu is staying. The next day, Asumu meets Hibiki out by the beach and they discuss what Hibiki does for a living. As Hibiki searches the mountain, Asumu follows him and is attacked in the woods, where he is rescued and witnesses Hibiki transform to fight the Hime and her child, a demon-spider called Tsuchigumo.

Both Adachi and Hibiki return to Tokyo where Hibiki is sent off to defeat a Yamabiko sighted at Okutama. Later on, Hibiki meets Asumu�s mother, who is ecstatic to see him. Meanwhile, the strain of studying for entrance exams begins to trouble Asumu as he worries about Hibiki and how safe he is with the type of job he has.

Asumu trails an old man whom he believes has connections to Hibiki after he sees him save a young girl. Elsewhere, Hibiki continues his battle with the Makamou who had been killing people in the forest. After the battle, Hibiki and Kasumi return to Tachibana�s sweet shop, where the Asumu and the old man are.

After a discussion with Hibiki about his plans after middle school, Asumu is reminded that he has no choice but to pass his entrance exam into Jounan, and he resolves to not see Hibiki until he gets in so he can share the good news. Meanwhile, Hibiki heads out after news that one of his comrades was injured in a fight, but can he handle an unfamiliar type of Makamou?

Ibuki, thinking Asumu is Hibiki�s apprentice, takes Asumu to where Hibiki and Kasumi are located. Hibiki and Asumu have a discussion about life and the challenges that everyone faces, leaving Asumu with a renewed passion to do well on his entrance exams. Hibiki then returns to battle the Bakegani that defeated him previously.

Excited over passing his entrance exam for Jounan, Asumu rushes to tell Hibiki the good news but is told he is training at a shrine deep in the mountains. Hinaka tells him how to get there and he sets off by himself. Meanwhile, Ibuki�s apprentice Akira arrives in the mountains and is attacked, forcing Ibuki to transform to fight a flying Makamou.

Lost in the forest, Asumu stumbles onto Ibuki�s camp where an irritated Akira tells Asumu that he will only hinder Hibiki if he continues following him around and that it would be best for him to leave. Asumu wonders just how true her words are and asks Hibiki himself how he feels about it after he arrives at the camp. Ibuki then defeats the Ittan-momen and Akira and Asumu make amends with each other.

Spring break has started and Asumu has already gotten off on the wrong foot, having missed going to the movies with his friend. He spends the rest of the day wandering around town and eventually encountering shoplifters. Meanwhile, Hibiki looks to see if his training paid off by taking down an Ooari while Ibuki and Akira track down a Makamou that seems to be a little more than they had suspected.

Asumu continues to wander through town after being a witness to the shoplifting, not really sure of himself and what to do next. Meanwhile, Hibiki and Ibuki team up to take down a very rare Makamou, Otoroshi.

A new school year has started and Asumu enters high school but still has mixed feelings on the path of life he has taken. Through all the aimless wandering he finds himself back at Tachibana�s Sweet Shop, but Hibiki has traveled out to the countryside after a call about people strangely disappearing where he faces off with new armored versions of the Douji and Hime.

After going through a false wall in Tachibana�s Sweet Shop, Asumu stumbles upon the Oni R&D room where Midori shines some light on Hibiki�s past. Meanwhile, Hibiki believes he�s discovered the secret to defeating the Armored Douji and Hime and begins to time their transformation, but he has to hurry as a Nurikabe is making its way towards the village below the mountain!

Hibiki goes to Asumu to ask him for a favor but Asumu doesn�t seem to be feeling well, and is rushed to the hospital when he collapses during class! In the mountains, after being given a power boost, an Ubume Douji goes berserk, killing the Ubume and the Hime, and proceeds to hunt down other Makamou, interfering in a battle Danki was engaging in before moving on to attack Ibuki!

Asumu is suffering from appendicitis and is rushed into surgery, as his high school life comes to a halt until he heals. Hitomi runs into her cousin while Asumu meets a man who gives him some advice as he leaves the hospital, as Hibiki and Ibuki team up to track down and destroy the berserk Douji.

Asumu returns home after spending a week hospitalized and begins his recuperation. Elsewhere, Zanki reveals that he will soon be retiring and expects his apprentice Todoyama to take his place, a revelation that Todoyama is less than pleased with. Even more, they are called to aid Sabaki at Tsukama Village, where a Yamaarashi is running rampant.

Zanki and Todoyama come to Sabaki�s rescue after being captured by the Yamaarashi, but Zanki begins to weaken and proves unable to defeat it. Todoyama takes Zanki�s place and destroys his first giant-type Makamou. As Zanki retires, Todoyama refuses to take his name, instead wanting to make a name for himself, as Zanki dubs him Todoroki, the Roaring Oni.

Kasumi and Ibuki go clothes-shopping on their day off. After shopping and during their meal, Ibuki sees a Douji and Hime pair in the city and begins his pursuit. Elsewhere, Hitomi is having mixed feelings about Asumu and Akira spending so much time together. After defeating the Douji/Hime pair, Ibuki is attacked by a Makamou that eats his disk animals as he waits for Akira to arrive with his Reppu!

Akira makes her way towards the ever-changing location of the Oonamazu but as she heads towards the battle, a puppet-type Makamou causes her to collapse under a bridge. Meanwhile, Asumu heads to Tachibana�s to drop off his notes and ends up helping Hinaka deal with the influx of customers. Finally, having tracked down the Oonamazu, Ibuki proceeds underground into the sewers to fight it for the final time�

Asumu begins his first day at Tachibana�s and discovers that Todoroki and Hitomi are related. Todoroki continues to fight the Bakegani as Kasumi notices something is wrong with him, while Zanki later arrives after he is called by Ichiro to examine a recording of Todoroki�s peculiar fighting style. Meanwhile, Hibiki practices on a dirtbike while waiting on standby�

Zanki visits Todoroki on the battlefield to question about his style of fighting while Asumu begins to have troubles at Tachibana�s and is then pulled into a conversation with Ichiro about the Oni. Hibiki later joins Todoroki in a fight against an Amikiri as Zanki makes a decision about his and Todoroki�s future.

While Hibiki enjoys a day off of fighting to run errands with Asumu, Ibuki and Todoroki are separately following two groups of Makamou that are heading towards Mount Asama. The Oni find it strange that the Makamou don�t want to fight nor do they attack humans, so just what is at the top of the mountain that draws them?

As Asumu and Mochi wait for Hibiki to return with the doctor, Akira is injured as Ibuki and Todoroki combine their strength to defeat the pair of Douji and Hime, but the Ubume and Yamaarashi are nowhere to be found. What they do find is a new, disturbing hybrid of the two Makamou and despite their best efforts, they can�t defeat it alone. Just then, Hibiki arrives as backup�

Hibiki takes Todoroki to his mountain training temple to teach him how to play the taiko so that the Oni are better prepared to deal with the summer Makamou, which are resistant to stringed instruments. Unfortunately, the training seems to be too intense for Todoroki, who loses faith. Meanwhile, Asumu is assigned the whistle in his high school�s brass band and is not too pleased with not having the chance to play the drums.

Discovering the self-multiplying Dorotabou, the Oni realize they will have to unify their powers using taiko to defeat the Makamou. As Hibiki trains harder to unleash his Crimson form, Todoroki struggles with his lack of drumming skill, but a pep talk from Hinaka might just be what he needs�

After Sabaki is defeated by a Kappa, Hibiki is sent out to finish the job. At the same time, Asumu, Hitomi, Hinaka, and Todoroki enjoy the day off by going to a water park where they run into Tsutomu Tsumura, who works at the park but has ties to the Oni world.

Everybody is out, either enjoying their day off or hunting down Makamou, leaving Asumu and Akira to tend to the sweet shop. Ibuki crosses paths with a strange couple that are dressed in full kimonos in a busy city while Hibiki and Todoroki track down a Bakeneko group hidden deep within a mountain forest.

Zanki is attacked by a white Puppet, and the damaged disks lead Hibiki and Todoroki to track down the group of Bakeneko hiding in the forest shrine. Back at Tachibana�s, Tsutomu reveals his relationship to the Oni world to Asumu and asks what he wants to do in the future.

After being beaten up for revenge by the shoplifter he stopped several months ago, Asumu loses his normal cheerfulness. Hibiki sees this and decides to take Asumu for a forest hike while fixing his damaged drumstick. Meanwhile, Eiki is defeated by an armored Douji and Hime, so Ibuki and Todoroki are called in to avenge their fellow Oni.

After his fall where he loses his phone, Asumu blames himself and Hibiki confronts the boy about being too negative and self-conscious. Meanwhile, Ibuki and Todoroki combine their efforts and battle Douji and Hime, with Eiki joining them in the battle against the Makamou, but it escapes and makes its way toward Hibiki and Asumu�s campsite�

A new boy has transferred to Asumu and Hitomi�s school, Kiriya Kyousuke, and the new boy seems to be good at everything from language to sports and makes Asumu feel boring. Meanwhile, The Man creates a new Makamou that does not have a Douji and Hime and unleashes it in the busy metropolis.

After witnessing Hibiki in battle and seeing Asumu�s familiarity with the Oni, Kyousuke declares that Asumu isn�t as boring as he thought and attempts to learn more about Hibiki, shadowing him at Tachibana�s. Meanwhile, Asumu learns more about his mother�s divorce from his father and decides to set out to meet the man he doesn�t even really know�

Kogure Kounosuke, a strong-willed weapons designer for Takeshi, comes bearing a gift for the Oni who work at the Tachibana Sweet Shop: the Armed Saber. Unfortunately, the weapon is too powerful for a normal Oni and the repercussions for trying to use it is losing the ability to transform. But when a new Douji and Hime appear more powerful than any before, the Oni may have no choice but to risk using it in battle�

After losing the Armed Saber to the Super Douji and Hime, Hibiki and Todoroki lose the ability to transform. They find out that they will regain the ability to transform in one month, but that is too long with a Makamou running amok. Kogure suggests that the two Oni undergo a special training, under his guidance, to regain their powers.

Todoroki and Hinaka�s birthday date goes awry thanks to Todoroki�s clumsiness and Todoroki feels that he doesn�t live up to Hinaka�s image of an ideal man, leading to his love life problems affecting his job as an Oni. Meanwhile, Asumu sees Hitomi give a love letter to Kiriya and wonders if this is the end of the special friendship they shared.

Todoroki finds his romantic troubles are causing him increasing issues in battle as he loses focus, and Ibuki isn�t far behind him! As Zanki tries to help Todoroki regain his confidence and get back on Hinaka�s good side, Hibiki tries to give Asumu advice after the boy falls into a depression after what he saw involving Mochida, a matter which Hibiki himself doesn�t have much experience in himself�

A mysterious Oni Armor, that gives the wearer the power of an Oni, has been stolen from a shrine. The thief uses it to attack Oni and Makamou alike; leaving the Oni wander what is the thief�s motives for using the armor. Meanwhile, Akira struggles with her hatred for the Makamou and what it means for her Oni training�

Having taken Todoroki�s transformation brace, Shuki sets out to get her vengeance on the Notsugo, despite the danger it poses to her former Oni comrades. As a result, Ibuki is tasked with the heavy burden of eliminating a fellow Oni, while Zanki struggles with who his former master has become�

When a powerful Makamou appears that is resistant to the Slaying Sounds of Ibuki, Todoroki, and Hibiki, the Oni struggle to find a measure to combat it while Ibuki also battles with Akira�s whereabouts since she departed with Shuki. Meanwhile, Asumu finds himself worrying about his self-worth after he is cut from the band as Kiriya grates on his nerves.

After Hibiki is defeated by the fearsome Yobuko, Ibuki searches for Akira, while Todoroki is severely depressed over his perceived failure with Zanki. Meanwhile, Kyousuke stumbles upon Takeshi�s armory and attempts to transform into an Oni, while Asumu and Midori attempt to escape the clutches of the Makamou before they are devoured!

A mysterious forest appears out of nowhere, causing the Oni to worry about what it could mean, and the mysterious Man and Woman also seem to be concerned with the new development. Meanwhile, Asumu believes he�s ready to become Hibiki�s apprentice while Kyousuke continues to beg Hibiki for the same thing, but both boys may be disappointed in his answer�

After Akira�s attempt at transforming, the Oni return to Tachibana�s where Asumu and Kyousuke are scolded for their attempts to become Akira�s apprentices. However, the boys are firm in their resolve to begin their Oni training, troubling Hibiki. Meanwhile, Ichirou meets with the mysterious Man and Woman, who warn him of the destruction to come�

With Orochi approaching, the number of Makamou has risen sharply, straining the Oni and their ability to handle it. With Hibiki taking Asumu and Kyousuke as his apprentices, the Oni are down even more, but even amidst the training, Hibiki rushes into battle, while Todoroki is gravely injured as he and Ibuki are overwhelmed�

After being crushed by a giant Makamou, Todoroki is rushed to the hospital, but while he survives, his prognosis is grim as he may never become an Oni again, driving him deep into depression while Zanki struggles with the situation. At the same time, Hibiki continues to train the boys, but Kyousuke�s arrogance and lack of physical skill holds him back, until he erupts with frustration at Hibiki�

Despite earlier warnings about transforming again, Zanki steps up and rejoins the fight against the growing hordes of Makamou, but it takes an extreme toll on him, but he intends to help Todoroki regain his strength no matter the cost�

Despite seeing him fall in battle, Ibuki is shocked to see Zanki appear in Todoroki�s room, but when Hibiki and Ibuki reveal Zanki�s fate, Todoroki angrily refuses to believe his mentor could be dead. As Kyousuke follows one of the boys that bullied him with Asumu on his trail, the approach of Orochi continues�

Leading the Oni to a stone with ancient Oni script on it, the Man and Woman make their next move towards preventing Orochi, but the cost of stopping it may be too much for Ibuki to bear. Meanwhile, Kyousuke becomes increasingly obsessed with becoming an Oni, with his focus on his training consuming him, while Asumu questions what it means to put your life on the line to protect others�

Coming to terms with what dying without regrets means to him, Asumu decides to walk away from his Oni training, leaving Hibiki seemingly disappointed, but with Orochi imminent, there�s no time to swell on it. Hibiki, Ibuki, and Todoroki set out to complete the ceremony, but Hibiki tricks the other Oni and escapes with his drumsticks, setting out for the purification site as the final battle begins�

Leading the Oni, Hibiki brings Orochi to a halt and purifies the earth as the ancient writings described. One year later, Asumu has moved on from Takeshi and the Oni and now interns at a hospital in his quest to find his own path to helping people. But when Mochida is captured by the Man and Woman as a new specimen for their experiments, Asumu�s path leads him back to Hibiki, Kyousuke, and the other Oni once again!

After Natsumi Hikari has a nightmare of every Kamen Rider being defeated by a figure called Decade, she helps her grandfather Eijiro deal with unsatisfied customers. The photographer, Tsukasa Kadoya, seems to be at fault, but he simply tells Natsumi the photos are bad because he does not belong in this world. After the argument, various holes in reality open, allowing the Orphnoch, Undead, Makamou, Worms, Imagin, and Fangires to start terrorizing their world. In the bedlam, she finds a corroded belt and book, recalling it as Decade's from her dream. She gives Tsukasa the belt and book, allowing him to transform into Kamen Rider Decade by using a card from the book and inserting it into the belt.

Arriving in the World of Kuuga, Tsukasa takes the guise of a policeman and watches Kuuga destroy a pair of Grongi, Ra-Dorudo-Gu and Me-Gyarido-Gi, before reverting to his human form, Yusuke Onodera. Tsukasa later destroys Go-Baberu-Da as Decade, but is mistaken for a Grongi by Yusuke and Ai. When Yusuke and Ai arrive at the Hikari Studio to discuss this strange Grongi, Tsukasa offers Ai his help in solving the mystery behind the Grongi's female targets and the location of their lair. On the foot of Mount Hitoki, the Grongi's Lair, Tsukasa reveals he used Ai as bait to lure out the remaining Grongi, revealing their plan to revive their leader before ruining their game. While attempting to destroy the Grongi, Decade is attacked by Kuuga, who reveals he knows about Decade's mission and will stop him at all costs.

After fending off the Hoppers who disappeared into another dimensional rift, Yusuke reveals he was told of Decade by a mysterious man. When Ai and her task force go to investigate Mount Hitoki, a black mist begins to rise from within, signaling the revival of N-Gamio-Zeda. Resurrected by the dimensional chaos, he uses his miasma to convert humans into Grongi. While Yusuke saves Ai and takes her to the hospital, Tsukasa fights the Grongi alone. A dying Ai requests Yusuke to overcome his angst and fight to protect everyone's smiles, and so Kuuga and Decade work together to destroy the remaining Grongi. N-Gamio-Zeda, in a last effort, absorbs all the Grongi to power himself up, but he is ultimately overpowered by both Decade and Kuuga, who destroy him with a combo attack.

Arriving in the World of Kiva, Tsukasa and company discover that the Fangires of this world have made a truce with the humans. However, when Tsukasa finds the Lion Fangire attacking a young woman, he transforms into Decade to fight him. Wataru, the King of the Fangire Race, witnesses this and becomes Kamen Rider Kiva to fight him with the aid of his Arms Monsters, forcing Decade to assume Kamen Rider Kuuga's Mighty, Titan, and Dragon Forms to counter. Yusuke manages to stop the fight, and the Swallowtail Fangire reveals that the young woman was actually a renegade Fangire. Yusuke reveals he has promised to help Wataru because he is uncomfortable with being the King.

As Tsukasa is fighting against Kaixa in another dimension, the Beetle Fangire defeats Wataru and becomes the new Fangire king, claiming Kivat. After the new King dissolves the truce, Yusuke arrives to protect Wataru before the boy runs off. After Yusuke expresses his reasons for helping the dethroned boy, Wataru takes refuge in the Hikari Studio. After being caught up on current events, Tsukasa makes his way to Castle Doran to save Yusuke as the Beetle Fangire absorbs the Arms Monsters into himself. After destroying the Swallowtail Fangire, Decade encounters the Beetle Fangire, who assumes Kiva's DoGaBaKi Form. When their fight makes its way to Yusuke and Wataru, the boy finds his courage to overcome his Fangire impulses and declares himself the King once more.

Upon arriving in the World of Ryuki, Natsumi goes to the Atashi Journal headquarters to learn about the world's Kamen Riders from its editor, Reiko Momoi. After Natsumi's arrival at the journal's offices, Reiko is mysteriously murdered, leaving Natsumi as the culprit as she had a small fork in her hand. Natsumi is arrested under suspicion of murder, and is to be sentenced with a Kamen Rider Trial: a system where Kamen Riders fight in the Mirror World to determine the outcome of criminal cases. Natsumi calls upon Tsukasa to be her lawyer, who meets with Shinji Tatsumi to hear what he knows of what happened to Reiko. As Shinji reveals that he is Kamen Rider Ryuki and he believes Natsumi was framed, his former friend Kamen Rider Knight is fighting in the Kamen Rider Trial, defeating several opponents. Shinji suggests to Tsukasa that he should fight as Decade in the Kamen Rider Trial to clear Natsumi's name.

After defeating Knight, Decade is about to finish him off when Ryuki pleads with him not to deliver the final blow, as he feels Knight must answer for his crime by his hand. However, Abyss uses this time to make his move to take out all three Riders at once, forcing them to retreat with Ren refusing to answer Shinji as he leaves. After her brief encounter with Narutaki, Natsumi learns that Shinji and Tsukasa are convinced that Ren is Reiko's murderer, although Yusuke sees otherwise. Meanwhile, a wounded Ren battles Kamen Rider Odin and defeats him, emerging from Mirror World with Odin's Time Vent as Shinji and Yusuke find him. Learning that Ren obtained the card to save Reiko, Shinji uses the card to go back in time as Tsukasa holds Abyss off. Arriving seconds before Reiko's death, Shinji and Tsukasa manage to save Reiko with the latter cornering her true murderer, Kamata.

Arriving in the World of Blade, Tsukasa assumes the disguise of the Chief Waiter of the BOARD Corporation, an organization whose agents become Kamen Riders to battle the Undead. When the Elephant Undead goes on the attack, Sakuya Hishigata battles the Undead as Kamen Rider Garren as Kazuma Kendate arrives and transforms into Kamen Rider Blade. When the Capricorn Undead joins the fray, Tsukasa joins the fight, dispatching the Elephant Undead using Ryuki's powers. Afterwards, Natsumi and Yusuke meet BOARD's president Hajime Shijo, who decides to promote Tsukasa to the rank of King while Kazuma Kendate is demoted from Ace to 7 and Mutsuki Kuroba is promoted from King to Ace, thereby becoming Kamen Rider Leangle.

Decade continues his fight with Chalice, with Garren losing his Garren Buckle in the process. The fight comes to a sudden halt when Kamen Rider Todoroki shows up. Back at BOARD, Hishigata is demoted to Rank 3 while Kazuma is fired from BOARD. After he understands Tsukasa's intent to help him, Kazuma stays on in the kitchen as he opens the Ace Lunch to all BOARD members. Meanwhile, Mutsuki and Hishigata search for Chalice to get back the Rider systems, and are subsequently ambushed by Chalice, who knocks them out after they find out his true identity. After hearing that the two have supposedly resigned from the company, Kazuma decides to find Hajime with Yusuke's help.

Upon arriving in the World of Faiz and once more encountering the mysterious Daiki Kaito, Tsukasa finds himself in a school uniform and enrolled at Smart Brain High School. He learns that the high school is attacked on a nightly basis by beings called the Orphnoch, with only Faiz to protect the school. Daiki challenges Tsukasa to find out who Faiz is, and Tsukasa then challenges the Lucky Clover clique to a tennis match to see if any of them are Faiz. He beats them, learning that they are Orphnoch who are also after Faiz, and is forced to become Decade, using Blade's power against them. However, Decade is outclassed when Momose appears as the Tiger Orphnoch and warns him to back off.

After Tsukasa recovers the Faiz Gear, he learns Diend's reasons for wanting the belt before Takumi regains it so he and a shocked Yuri can escape on the Autovajin. However, as he exposed himself as the Wolf Orphnoch to protect her only to be forsaken, a saddened Takumi attempts to dispose of the Faiz Gear into the river. Managing to save the Gear while following him, Tsukasa returns to the photo studio where he put Yuri's confusion at ease. The next day, Daiki attacks Takumi to get the belt from him, nearly killing him when Tsukasa arrives with it. Refusing to take Tsukasa's words of something more precious than the Faiz Gear seriously, Daiki takes Decade's Ride Booker, and Narutaki takes advantage of the situation as he takes Tsukasa into another dimension to be killed by Kamen Rider Ryuga.

Upon arriving in the World of Agito, Yusuke is shocked that there are Grongi in the world which are being dealt with by Kamen Rider G3-X. He is further shocked when he sees an interview with Toko Yashiro, who is physically identical to the Ai Yashiro that died back in the World of Kuuga. Arriving at the police station, Yusuke offers to be the new user of the G3-X suit, but loses the position to Kaito. While this occurs, finding himself in a mailman outfit with a letter to Shouichi Ashikawa, Tsukasa and Natsumi find the man before they are attacked by what they think to be a Grongi. But during the fight, Tsukasa realizes he is fighting an Unknown, an Ant Lord called Formica Pedes.

After Yusuke saves Tsukasa from Delta's attack, Gills is about to fight when he's overcome with pain as the Unknown shows up to kill him. As Shouichi escapes, Toko recognizes him via G3-X's camera. While Tsukasa insists on protecting an annoyed Shouichi, Yusuke reports the defeat of the Grongi and the emergence of the Unknown. He finds Toko saddened, but has little time to help her as Kaito takes the G4 chip stored within his locker. Yusuke demands the chip back, but during the struggle, Toko blasts the chip to bits and a disappointed Kaito leaves. The next day, as Tsukasa continues to keep Shouichi safe from the Unknowns' attack, Yusuke learns that Shoichi was the original user of the G3 suit when he receives the letter for Shouichi from Toko.

When the Hikari Studio appears in the World of Den-O, Tsukasa finds himself dressed in a strange detective-like attire with possession of a Rider Pass. He is then suddenly possessed by an Imagin, who battles a Mole Imagin as Kamen Rider Den-O. After taking out the Imagin, the possessed Tsukasa walks off until Natsumi uses her pressure point move to drive the Imagin out of him. When the Imagin known as Momotaros tries to possess Tsukasa, again, he throws Yusuke in front of him and Yusuke becomes possessed. After easily overcoming M-Yusuke and treating him to pudding for answers, Tsukasa learns that the Imagin lost his physical form some time before they arrived.

After getting on the DenLiner, Tsukasa takes pictures of the DenLiner's gang before the Taros. But after Kohana sets the three Imagin in their place, they suddenty find the Hikari Studio as the front car. Kohana explains to Natsumi about the Imagin's new attack pattern as well as Momotaros, who Tsukasa decides to find. After surviving his confrontation with Diend and taking out another Mole Imagin, M-Yusuke tends to his injuries as Tsukasa finds him and scolds him for being an idiot. M-Yusuke senses the Imagin boss, and he and Tsukasa chase after the Alligator Imagin until he reveals himself. Using the Mole Imagin to cover his escape into the past, the Alligator Imagin battles Den-O and Decade, using the former's own DenGasher against him.

After helping the DenLiner gang in the past, Tsukasa and company begin their venture in the World of Kabuto. Posing as a ZECT Trooper, Tsukasa is deployed to aid Bright Troopers in the containment of a Worm as Kamen Riders Gatack and TheBee manage to exterminate it with the unseen aid of Kabuto. Soon after, Tsukasa brings Arata to the Studio to explain about his world, only to find a Worm had mimicked Tsukasa's form. After Natsumi uses the pressure point to expose one of the Tsukasas as a Worm, Decade fights it before it attacks a girl and is destroyed by Kabuto. Deciding to investigate the girl Mayu, they host a photo shoot for her, and Natsumi learns of Mayu's older brother who was supposedly killed by Kabuto. At ZECT's headquarters, TheBee's user, Sou Otogiri, tells Arata that the final prepation for the plans to capture Kabuto are nearly done.

Believing that TheBee's user is her brother, Mayu attempts to look for him with Natsumi's aid until they are attacked by a Worm. Counting on Kabuto to save them, Diend fights him to acquire his Clock Up system, summoning Ixa and Psyga to hold him down before Kabuto defeats them and runs off. By the time Tsukasa finds Natsumi and Mayu, the latter is shocked that she became a Worm as she runs off. She runs into Sou who reveals himself as the Phylloxera Worm and brings her to ZECT HQ as part of the Kabuto Capture plan, much to Arata's dismay before he is beaten to a bloody pulp questioning the plan. After escaping, Arata makes his way to Tsukasa and reveals the plan to him, confirming Tsukasa's notion. Kabuto falls for the trap as the Clock Down takes effect while the Worms reveal themselves among the ZECTroopers, with Sou exposing Kabuto as Mayu's real brother Souji.

Arriving in the last world, the World of Hibiki, Tsukasa and company begin the search for Kamen Rider Hibiki when they are ambushed by the Makamou Kappa. An Oni in training named Asumu battles the monster until Decade uses Kabuto's powers to destroy it. On learning he is Hibiki's pupil, Tsukasa has Asumu bring him to his mentor. Upon seeing Tsukasa, Hibiki, who is shirking off from his duties as an Oni, believes him to be the legendary Ongekidō Grand Master. Meanwhile, Zanki slays a band of Bakeneko as Ibuki arrives to take them out as well. But when the last Bakeneko escapes them, Decade destroys it with the two groups as witness. Tsukasa visits Ibuki's school afterwards and talks with Ibuki and Akira about three special scrolls. Meanwhile, after failing to rob Hibiki as he takes his leave, Daiki is forced into becoming Asumu's mentor.

Using Ryuki's powers, Decade battles Gyuki while Ibuki and Zanki argue whose fault this was. When Akira and Todoroki join the fray in their Oni forms to save Asumu as he tries to protect them, with Decade joining them by using Den-O's Ax Form, they manage to defeat Gyuki. He runs off before regressing to Hibiki, and Yusuke and Natsumi find him shortly after. Later that night, after talking to Asumu, Akira and Todoroki confront their mentors to put aside their differences, with Tsukasa supporting them. Ibuki and Zanki promote them to the role of new teachers of their respective schools. Meanwhile, Hibiki reveals the nature of Gyuki to Yusuke and Natsumi as Daiki arrives to claim the last scroll.

With their tour of the nine Kamen Rider Worlds complete, the Hikari Studio group returns to their home world, finding it as it was before the monsters appeared. Tsukasa is the only one who feels something is not right and questions the reason for the journey. Before Yusuke or Natsumi can attempt to answer, they encounter the violinist Otoya Kurenai, who thanks them for saving the world and tells Tsukasa that he earned a world of his own for his journey. As Natsumi goes out to see her TG Club friends and teacher for a high school reunion, Tsukasa and Yusuke have a short encounter with Narutaki who congratulates him on getting his own world.

After Tsukasa suddenly loses his powers, he learns from Kaito that he is actually in the World of Negatives. He later is seen by a talent agent and is offered to be signed onto his agency to become an idol. Although Yusuke acts as the voice of reason, he gets caught up in the fame seeking as well. Meanwhile, after her school friends return while waiting for Chinatsu, Natsumi that suggests that they should dig up the "treasure" they buried together, only to find that a parking lot was built over it and learning that Chinatsu moved their treasure prior. Once, Tsukasa finds Natsumi, he attempts to tell her that they are not in the real world, but Natsumi refuses to accept this as she runs off to the TG Club's hideout where she also meets the World of Negatives's Natsumi.

Arriving in Kaito's homeworld, the World of Diend, Tsukasa finds the world in peace and harmony, but with Kaito a wanted man. As Tsukasa assumes the role of a traveling salesman, he meets Kamen Riders Larc & Lance as they battle a Darkroach. After destroying the monster, Tsukasa learns that the world's residents kill Kamen Riders. As Tsukasa and company meet the head of area management committee, Junichi Kaito, Larc and Lance battle the Darkroaches until they receive aid from Diend. Saving them from reinforcements, Tsukasa learns from Haruka and Shin that the world is ruled by the mysterious Fourteen who uses his Roaches to manipulate humans.

Nearly killed by Lance, Kaito is spared when Larc stops her partner as he reminds her that he is the reason that Junichi is under Fourteen's control. After escaping the angry mob, parting from Haruka and Shin, Kaito and Tsukasa find Natsumi who tells them that Yusuke has been kidnapped by the Roaches before Junichi arrives. After remembering the events leading to his brother's enslavement, Kaito is reluctant to fight as he and Tsukasa transform to follow Junichi, leaving the brain-washed Yusuke behind and taking Natsumi to undergo the process as well.

Arriving in the new world with a strange card in hand, Tsukasa finds himself in the costume of a kuroko before running into Daiki who just stole a squid-like artifact. Daiki mentions that this world is not like the other A.R. Worlds before running off prior to the appearance of mysterious red fish-like monsters. Tsukasa is about to transform before several other Kuroko show up along with five young men and women who transform into the Shinkengers to fight drive them back into the Sanzu River.

After Tsukasa reveals himself, Takeru realizes that Tsukasa is the "Decade" Narutaki warned him about. Before the two can fight, Narutaki arrives to tell Tsukasa he is to blame for the terror brought unto the world by the Ayakashi Chinomanako who now has the powers of Diend, and that the only way to save the worlds he entered if he ceases to exist. After Takeru takes out the Nanashi and drives off Chinomanako as Shinken Red, Genta attacks Tsukasa believing that he is in league with Daiki until Natsumi takes him to the Hikari Studio, where Hikoma Kusakabe is hiding.

Tsukasa finds himself wearing strange clothes with another strange card as he, Natsumi, and Yusuke find themselves attacked by the Strange Demon Robot Schwarian and his Chaps as Kamen Rider Black RX battles them, with both sides believing Tsukasa to be Joe the Haze. When the Seamoon Fangire and Scorpion Imagin suddenly appear, Tsukasa becomes Decade to help RX out against the monsters with Agito's power as Schwarian runs off. After Natsumi stops RX from attacking Decade, RX takes her words to heart and sees Tsukasa as an ally.

Following Apollo Geist into another A.R. World, Decade is attacked by Kamen Rider Black until Diend arrives and summons Femme to hold him off. The next day, after learning that he is in the World of Black and seeing that he is on his own in saving Natsumi, Decade ambushes Guy as Ryuki and fights him until he uses a little girl as his hostage. When Decade takes a hit from Diend to save the child, Black watches and has second thoughts about him as Apollo Geist escapes.

Arriving in a new A.R. World, finding himself in a baseball uniform, Tsukasa notices the people are acting strange while saluting each other before he, Natsumi and Yusuke are singled out as rebels against Dai-Shocker with Propheta Cruentis, Go-Jaraji-Da, and Camponotus Worm Maxilla appearing to exterminate them. Amazon arrives to their aid, fighting the monsters with Decade backing him up as the people back up the surviving monsters under a boy named Masahiko.

Evading Apollo Geist and Llumu Qhimil with Diend's attempt to get the GaGa Armlet, Tsukasa has his wounds tended to by Natsumi in Dai-Shocker's school before Yusuke and a weakened Amazon join them, revealing that Masahiko took the GiGi Armlet as Ritsuko arrives and calls in the Dai-Shocker Soldiers after them despite Tsukasa questioning her faith in Dai-Shocker. Later after finding the Hikari Photo Studios in ruins, Amazon ponders if he should join them.

When Natsumi realizes that this is the world from her nightmares, she becomes wary for Tsukasa's well-being. Finding him in a tuxedo and feeling that this is the final chapter to their journey, they witness Wataru and Kazuma leading their respective Rider/monster groups against each other. After Rising Ixa and Leangle are killed off in the fight, Tsukasa makes his way to Wataru as he grieves over Ixa's death. Meeting the Fangire Queen Yuki, they learn from Wataru that the Riders are fighting each other to maintain the existence of their worlds.

After fighting off the Riders, Super Apollo Geist takes Natsumi to be his new bride as he flees. Kazuma Kenzaki appears, saying that Tsukasa's existence is the real cause of the worlds blending before confronting him as Kamen Rider Blade in King Form in order to force him to leave the world at once with Asumu keeping Yusuke and Wataru from interfering as Decade is easily defeated.

Sougo Tokiwa seems like an ordinary high school student, but one thing he has different is that he has dreams of becoming a king! One day, a mysterious young man appeared before him with a prophecy. "Congratulations! Today is a special day for you..." As Sougo is told these words, a giant red robot suddenly appears before him! This robot was a time machine, and Sougo was thrust across various timelines! In the year 2000, the battle of the Heisei Rider's fate, and Sougo's fate in his own birth year, is about to begin...!

The man who hails from the future, Geiz, attacks Sougo! Tsukuyomi, a girl who also hails from the future, came to help out Sougo, but Sougo has absolutely no idea what's going on! A mysterious prophet named Woz is also starting to appear frequently before Sougo. The creature, Another Build also attacks. What could be the key to defeating this "Kamen Rider Build"? Sougo makes his way towards the Nascita Cafe to meet with Kiryu Sento...

A strange collaboration between Geiz and Tsukuyomi happens with Sougo in the year of Build, 2017. They both decide to go to Sougo's school to keep a closer eye on him. While there, they discover a growing popularity of a "game that no one can clear" with the other students. Rumors surrounding the Genius Gamer M start to surface as well, as they decide to chase the mystery by finding him. And Sougo and the others end up meeting...? Suddenly, a new Time Jacker, Ora appears!

Ora has given a father the power of Another Ex-Aid as part of a bargain for his son's life. Geiz and Sougo travel back to 2016 to help him.

Tsukuyomi and Geiz learn that 18-year-old Libras have been going missing from Amanogawa High for years and want to check it out, thinking that it's probably an Another Rider plot; Schwartz makes his presence known to Uhr and Ora, forcibly creating a new Another Rider.

Takumi joins Sougo in protecting Karin from Another Fourze; Tsukuyomi and Geiz learn that Karin is actually much older than she looks.

Sougo learns of a magic show and wants to check it out. After seeing the magician in action, Geiz believes that he might have been given the powers of Kamen Rider Wizard and wants to fight him.

Geiz tracks down Kousuke in order to get his hands on the Wizard Ride Watch.

Uhr gives Kuroto Dan the powers of Kamen Rider OOO, which leads to Kuroto declaring himself king in 2018. Sougo finds common ground with this new Kuroto and wants to learn from him.

Sougo asks Kuroto just what type of king that he wants to be; Tsukuyomi learns to listen to all points of view.

Sougo and Tsukuyomi search for Geiz when Sougo notices the news that Team Baron dancers have been disappearing, but Tsukuyomi gets fed up with Sougo constantly returning just after leaving and having an inconsistent memory.

Sougo is revealed to have traveled back in time to save Geiz, and so there are two of him in the present, but Woz isn't very keen on this plan.

Takeru Tenkuuji and company have been hired by a woman to investigate Another Ghost after her brother mysteriously disappeared; a confrontation occurs with what appears to be Kamen Rider Agito.

With Sougo's soul separated from his body, he guides Takuru back to the year 2015 where Geiz has his Ghost watch taken from him in exchange for a Decade one.

Oma Zi-O sends a fleet of Dai Mazine to 2018 and a loyal follower to take out Geiz and Tsukuyomi; Tsukasa sends Sougo to meet his future self.

Sougo returns from the future and destroys his belt, ensuring that he will not become Oma Zi-O, but he is later attacked with no one to turn to for help.

Sougo has a dream that he is in the year 2022 and meets a man who goes by Kamen Rider Shinobi. Later, he encounters an Another Rider with the same attacks and a second Woz appears.

Sougo and crew are confused over the appearance of "White Woz"; Geiz and Tsukuyomi try time traveling to get the Kamen Rider Shinobi watch but are forbidden to land.

Sougo and Geiz head into battle with an Another Rider when the original Rider also arrives on the scene. How are both Kamen Rider Quiz and Another Quiz active at once?

Sougo works with Mondo to get answers from his dad and Geiz works with "White" Woz to stop Another Quiz.

Heure breaks a mirror and gives an Another Rider watch to a man inside; Sougo and Geiz have trouble defeating an enemy who keeps retreating even though he has nowhere to run.

Sougo battles with his self on the other side of the mirror; Geiz tries defeating Another Ryuga when things go horribly wrong.

Sougo falls asleep while studying and travels 100 years into the future to a world where humans and machines are at war; Tsukuyomi joins forces with White Woz.

Sougo dreams of Kikai going evil while Ora asks White Woz for help with Heure; Geiz asks Tsukuyomi if she really wants to align herself with White Woz.

A man with a connection to Sougo's past is taking the leftover energy from previous Another Riders.

Tsukuyomi travels back in time to investigate Hiryuu Kakogawa; White Woz tells Geiz that his watch won't activate until he's committed to killing Sougo.

After getting beat by Geiz, Black Woz goes to Ora and Heure for help; Schwartz recalls the first time he met Tsukuyomi.

Tsukuyomi learns about Sougo's past; Sougo and Geiz prepare for their showdown.

Kamen Rider DiEnd runs off with Sougo and Geiz's watches when Tsukuyomi gets word of Another Blade; Sougo forces Woz and Geiz to work together.

White Woz has Blade and Chalice fight to bring on the end of the world; Black Woz and Geiz settle their differences.

Sougo and crew watch a news report of the G3 unit getting attacked by Another Agito. When they arrive during another attack, Sougo learns that Another Agito is able to multiply and one freezes in front of Tsukuyomi.

The Timejacker steal the real Agito's power; Woz questions Schwartz about Tsukuyomi's newfound abilities.

It's Sougo's birthday and Woz wants to make it special; Sougo's former classmate who wanted to become an oni is turned into Another Hibiki.

Kyousuke has been outed as not being Hibiki; Sougo has Todoroki take Woz as his pupil for the day.

Sougo recalls his first love from elementary school; Ora recruits a woman falsely accused of murder to become Another Kiva; a new Kamen Rider falls from the sky.

Schwartz calls a temporary truce with the Kamen Riders to stop Ginga; Sougo tries to get Yuuko to stop her revenge.

Sougo and the others watch a news reporter turn into a monster; Tsukuyomi remembers a piece of her childhood; a meteor is heading for Earth.

The Hell Brothers steal the Fourze and Ginga watches so that Sougo and Woz cannot stop the asteroid; Tsukasa takes Tsukuyomi to visit her childhood home.

The DenLiner breaks down and the Imagin go to Junichirou to fix it; Yuuto Sakurai and Deneb emerge to stop Sougo from obtaining an unstoppable power.

Momotaros is warned about the demon king by Yuuto, taking back the Den-O watch in the process; the gang must travel back to 2011 to stop the Mole Imagin.

After being defeated by Oma Zi-O, Sougo arrives back in 2019 where all his friends have turned against him and his only ally is a passing through Kamen Rider.

Tsukuyomi saves Sougo from an attacking Geiz; Schwartz recruits Daiki Kaitou after he's caught stealing from Another Zi-O.

Schwartz reveals to Tsukuyomi that they are siblings; Ora and Heure are relieved of their Timejacker duties.

Kamen Rider Aqua arrives in a prototype Time Mazine to take Geiz and Tsukuyomi back to the future; Heure and Ora seek shelter with Sougo after being attacked by Another Drive.

Geiz doesn't trust Heure after finding out that Ora is Another Drive; Schwartz uses his powers to summon Kamen Rider Eternal.

Sougo and crew attempt to make a deal with the newly revived White Woz to save Geiz.

Sougo is given an ultimatum regarding his path by Schwartz and takes Tsukuyomi to visit her own time; enemies that should be defeated because of the previous Kamen Riders are now all returning.

Tsukasa has a plan to stop Schwartz, but it doesn't involve Sougo surviving the outcome.

Tsukuyomi has transformed into a Kamen Rider and the final battle has begun.