The barrier to the Northern Base has been breached, letting in members of both the Southern Base and the Megiddo.

Touma and Rintarou head out to retrieve Kento and Ren while Master Logos schemes to get the remaining swords.

Touma pleads for Kento to fight with the other swordsmen as they battle Master Logos.

Touma is able to win over Kento, but there is still unfinished business with Ren and Master Logos.

Touma and Kento encounter a reminiscent trio who are being targeted by a monster that is being hunted by a strange man with a demon inside of him.

Giff is ready to revive when the Igarashi siblings discover that Hiromi is still alive, but does not remember anything, and so everyone devises a plan to create a film to help him remember.

Houtarou is a high school student in search of his own "Gotcha" (something unique to him). However, he is still in a daze, unable to even decide on a career path. His classmate Rinne looks down on him.

Then, Houtarou meets a grasshopper. "I don't know what it is, but when I'm with you, I feel a stirring in my heart..." Then, Steamliner suddenly appears and takes Houtarou to another space. In the other space, a mysterious man entrusts Houtarou with a Driver, saying it is his hope for the future. Then an enemy attacks!

The target is Houtarou's Driver. Houtarou loads the card into the Driver! He transforms into Kamen Rider Gotchard..!

After transforming into Kamen Rider Gotchard, Houtarou wants to learn more about the Chemmies and is advised by his teacher Minato to take the entrance exam for the secret Alchemy Academy. However, Houtarou runs into a problem.

Meanwhile, Ryo Kajiki meets a talking skateboard who loves to play with children, but...

A boy appears in front of Houtarou and others, asking to take over Saboneedle. Since Ordinary people and Chemies cannot coexist, Rinne, who values the rules, tries to accept the boy's request, but Houtarou is not convinced.

Doesn't he really want to be with Saboneedle? Houtarou tries his best to find out the boy's true feelings, but then a new Malgam appears. What is the true identity of Malgam who is targeting the boy for some reason!?

Saboneedle flew out of the driver during the battle with Dragonfly Malgam. Houtarou senses something as Riku becomes more distraught than ever, asking, "Where has Sabosuke gone?"

Meanwhile, Atropos suddenly appears in front of Rinne...!

Supana returns to his master Kyoka Edami to have her repair his Valvarusher, which was heavily damaged during his battles with the Three Dark Sisters. As he arrives in her laboratory, he becomes intrigued by the blueprints of a new weapon she is developing.

A giant snake suddenly appears from the sky and attacks people with its petrification rays. Houtaro transforms into Gotchard and confronts the snake, who speaks in an eerie voice.

"Are you Kamen Rider...?"

What is the true identity of the giant snake?

While Houtarou is serving New Years Food to Rinne and the others, he's wondering who is the Orange Gotchard that appeared during Christmas, and the sudden strengthening of the Malgam...

Suddenly, a Malgam appeared before Houtarou! Houtarou transformed into Gotchard, but he struggled against the empowered Malgam. As the Orange Gotchard appeared, he tells the shaken young man "As you are right now, you'll never defeat that Malgam."

A suprising development awaits Houtarou and co. as a person starts to move after Geryon's revival...

Houtaro and Rinne are disappointed in a world where not only the Alchemy Academy, but also their teacher Minato does not exist. The Moon Malgam then appears in front of the two and mocks Rinne where it takes her into the shadows.

"What should I do to become stronger and defeat the Moon Malgam?", asks a worried Houtaro.

Gotchard Daybreak then replies. "I will transport you to the past."

Just what is in Houtaro's past? What should he do there?

Houtaro and the others are overjoyed to receive a letter from Minato saying that he will take down Geryon. They immediately rush to the location Minato has designated, but suddenly a new Malgam appears. Houtaro is deprived of all his cards except for Steamliner.

He is unable to transform into Gotchard. Houtaro still wants his cards back, so he consults with Kyoka and learns that there is only one way to transform, though it is a forbidden technique...

Houtaro transforms into Iron Gotchard, but his physical strength is depleted and the transformation is canceled. He is saved by Fuga, the father of Rinne, who suddenly appears and escapes from the battle with Dread Type One.

Fuga explains about "an incident" that occurred 10 years ago, which is the reason why Minato abandoned Houtaro and the others to follow Geryon. Houtaro and the others, who understand Minato's true intentions, confront him once again...!

Houtaro, who defeated the Malgam and got a new Chemy, was attacked by an angry Clotho!

With Geryon gone, what is the point of fighting? Houtaro fights back and pleads desperately, but Clotho refuses to listen to him. Then, suddenly something unusual happens and a new enemy appears to attack Houtaro and the others...!?

Saigetsu, Mimei, and Tasogare of a mysterious organization appear before Houtaro and the others. The three, who say they are looking for a super weapon in this world, call in the Kasshine army to attack the people.

We will stop them! In front of Houtaro and the others, who are furious, Saigetsu and the others transform into Kamen Riders such as Dark Kiva! Houtaro, Rinne, and Supana also transform into Riders and stand up to them...!

Kaguya, who is reunited with Houtaro, comes to Furasu High School and charms the students with his "gorgeousness." Houtaro is taken aback by the notoriety that even a fan club has been formed.

Houtaro and Kaguya are again faced with the appearance of the Hundred's Kasshine army. Houtaro and the others transform into Riders and defeat them, but Kaguya utters ominous words about the leaders still being nearby...?!

Kaguya transforms into Legend and attacks Houtaro. Houtaro also transforms into Gotchard and fights back, but Kaguya shuts him down and says, "Gorgeous time is over," and leaves him alone.

They are supposed to have made up, but why? Houtaro and the others are puzzled by Kaguya's sudden change, but then a giant clock appears in the sky above them. What does the ticking of the clock mean? Moreover, the Dark King Gigist begins to act in secret...!?

Houtaro, who was spirited away from Rinne and the others by a giant egg, finds himself in a black space with a floating blue egg. "What is this place? Who are you?" Houtaro asks the egg.

Gigist stands before Supana, who was on his way to rescue Houtaro. Supana transforms into Kamen Rider Valvarad, only for Gigist to unleash the mighty Malgam, which he had created by rallying his Chemies, on Kamen Rider Valvarad!

Renge proposes a competition to retrieve the two remaining Chemies, with Nijigon at stake. Despite a stunned Houtaro, Rinne, Sabimaru, and even Nijigon get involved...!

Gigist appears before Houtaro. Gigist tries to dye the Chemies in darkness, but Houtaro uses the power of Nijigon to prevent him from doing so. He transforms into Rainbow Gotchard and clashes with Gigist!

Houtaro and his team receive information that the 102nd Chemy has unexpectedly appeared. Houtaro, Supana, and Sabimaru begin a search based on this information, and arrive at a certain research institute where Sabi's brother, Ken'ichi, works.

A new Malgam appears at the institute. Is the 102nd Chemy real after all? And behind it all is the resurrected Geryon!? Houtarou and Supana transform into Riders...!

Mami, the director of Kongo Laboratory, begs Houtaro and the others to protect the laboratory from Geryon. Protect it from Geryon? What is the relationship between Mami and Geryon...?

Houtaro, suspicious of the Chemy's behavior, asks Sabimaru if it was really Kenichi who created the Chemy. For a moment, Sabimaru is perplexed, but then he reveals the truth behind the Tsuruhara brothers and Chemies. What is that unexpected truth!?

Glion, transformed into Kamen Rider Eld by the power of the Philosopher's Stone, summons an army of Dreatroopers. The city and its people are transformed into gold, and El Dorado is steadily approaching completion.

Houtaro tells his mother, Tamami, that as a Kamen Rider he will create a future where humans and Chemies can live together, and that he doesn't want to run away from his Gotcha! He then joins Rinne, Supana, and the other Chemies in a final battle to defeat Glion!