Louise tries to prevent Saito from looking at other girls, but her plan fails. The newly crowned Queen Henrietta assigns the code name 'Zero' to Louise for a mission. When they get home Louise insists she tell him about the misunderstanding that Agnes said. When he tried to explain she beat him until morning causing bruises all over his body. The next morning, Saito and Louise are informed that Henrietta has been kidnapped.

The supposedly dead Wales appears and takes Henrietta to Albion. He uses his vow from their earlier days to convince her into following him. Saito and Louise goes to rescue Henrietta. Wales, later revealed to be revived and controlled by Cromwell's ring, is defeated by Louise with a dispel spell. Wales is released from the control of the ring and asks Henrietta to make a new vow with him before dying again.

Julio Cesare transfers to Louise's school and shows an interest in her. He challenges Saito to a fight in which the winner gets to kiss Louise. Saito receives special training from Agnès but Louise shows up and attacks Saito in a jealous rage yet again. He fights against Julio the next day, but Julio loses on purpose.

Eléonore drags Louise, Saito, and Siesta back to the Vallière house, where Louise is announced to be engaged to a duke. Saito goes to talk to her at night but instead finds her sister who beats him like Louise does. Saito confesses his true feelings to Louise, makes out with her in a childhood boat, fights his way out of the Vallière residence, and heads back to school with Louise. She doesn't believe him about what happened in an earlier incident and beats him again while Siesta tells herself she is the only one for Saito.

Louise's sisters move in and make Saito do the work. Siesta makes a pass at Saito when Louise shows up. Just when Louise was about to strike him with a newer whip an explosion happens. A thief stole something from the principal's office and the principal marked the woman with a magic seal on her chest. Saito tries to do it secretly but Louise finds him and tries to hurt him again. Then a commotion in her eldest sister room gets their attention. The thief is found out and when everything is done and over with because Saito didn't tell her what he was ordered to do along with other things that was justifiable she beats him with her new whip out of spite.

Saito and Louise are ordered to be at Scarron's inn to receive further instructions. They take their previous positions and costumes back, and are surprised by Gulio's appearance. Saito runs into Henrietta who asks him to protect her as she poses as a commoner in order to lure out one of her enemies. Saito and Henrietta evade detection from the soldiers searching for the Queen by behaving like sweethearts, while Louise learns of the details of the Queen's mission from Agnes. In a theater in town, while Scarron and his girls are in the middle of performing a play, Henrietta confronts her enemy.

Henrietta is convinced to sign a declaration of war against Albion. News of a victorious battle for the Tristain and Germania allied forces reaches a town that Louise and Saito are currently in. Saito discovers a sailor uniform on sale at a clothes merchants shop, and buys it, opting to give it to Siesta rather than to Louise. Upon returning to the academy, the two join Agnes and Julio on exploring a secret archive hidden beneath the school, which Agnes was denied permission. Agnes wishes to obtain the information there regarding her home town of D'Angleterre's burning to help carry out her revenge against those involved. Eleonore is picked to open to lock to the entrance. As the group heads farther down, they are joined by Siesta, who is wearing the sailor uniform Saito gave her earlier. After discovering that Saito gave the sailor uniform to Siesta because Louise lacked the chest size to make it look good, Louise blows a part of the cave in the way they came. With little to do but move further, the group finds the archives and are sent to look for the records regarding the town of D'Angleterre's burning 20 years ago. When Siesta trips and makes a mess of the books, Eléonore returns them to their proper place with magic, which triggers the archives' security system and begins to bring the bookshelves to a close. Agnes finally finds the information regarding D'Angleterre's burning, but a part of the page that lists the person who led the attack is missing. The group narrowly escapes the collapsing of the bridge that led them to the archives. Upon realizing that Louise had blocked their way out from before, Julio grants Saito permission to have intimate moments with Siesta. Siesta is happy to oblige and Saito also thinks it to be a good idea, however, Louise is watching and is preparing to blow something else up. When Saito points out that the cave in she made earlier is in the opposite direction, Louise tells him to shut up and blows them up anyway.

Albion sends hired mercenaries to make a surprise attack on the Magic Academy and take all of the people from the royal families hostage. Saito and his friends plan on how they will rescue the people taken hostage as it will take too long for the reinforcements to come from the palace. It is discovered the captain was one of those who attacked Agnes's town D'Angleterre's and burnt it to the ground 20 years ago.

Colbert sensei and Saito devise a plan to enter into the building and save the hostages. Benubiro explains to Anies how his captain Snake of the Flame ruthlessly burnt the women and children to ashes. The team use their combined magic to enter the building. During the attack, Benubiro recognises Colbert-sensei who is in fact his captain Enja, Serpent of the Flame. The two enemies begin a heated battle. Agnes becomes furious and charges towards Colbert sensei. Benubiro fires a lethal fireball towards Agnes to stop her from interrupting them, Colbert-sensei pushes her away from the blast and is struck in the crossfire. Agnes takes her revenge for her town upon Benubiro and defeats him. Colbert-sensei in his last moments explains what had occurred on that fateful day. He had been given orders to destroy D'Angleterre's Town as it had been reported to be struck with a deadly plague. After discovering there was no plague, he discovers a girl (Agnes) the only survivor and he carries her to safety. Agnes is still infuriated and she holds up her sword to strike a final blow to Colbert-sensei, but he dies before she can do so. Louise and Saito are saddened by the death of their teacher, whereas Agnes is still undecided if she will ever forgive him.

Henrietta has a special mission lined up and Louise and Saito are the perfect candidates. But Saito hesitates to go into battle because of what Mr. Colbert mentioned before.

Henrietta's forces enter South Gotha and claim it. Scarron's traveling tavern sets up shop, and Saito and Louise are reunited with Siesta, Jessica, and Guiche. Guiche shows off a medal and relates a story of coming back from the dead, which no one believes. Using the Ring of Andavari, Sheffield causes some of Henrietta's troops to attack the city from within.

Are Louise and Saito being sent on a suicide mission? Before they even consider their safety, the couple has one last thing to accomplish and Louise wants to make a covenant.

Saito's runes disappear before his, Louise's and Siesta's eyes. While on a trip to the castle, they are attacked by Sheffield, who is revealed to be the familiar of an unseen Void mage that she refers to as "Master Joseph". After arriving at the castle, Saito is given a paper by the princess that would make him a knight and effectively a noble. He, however, turns it down on the issue that he does not believe he can protect the princess or Lousie without the familiar's contract. When asked about the disappearing runes, he tells them about the elf, whom he recalls as Tiffania. Derflinger tells them where they may find her so Louise and Saito prepare to depart. That night while worrying about recent events, Louise awakens to find Saito awake outside on the balcony. She tells him that she is afraid of him leaving again, especially with the disappearance of the runes. He reassures he will not leave despite the absence of any contract. However, when he tries to have sex with her, she blows him up.

While they are traveling to the village where Tiffannia is living, they meet up with Siesta who is carrying cooking supplies and food. At the same evening, while they were having dinner, Louise gets into another fight with Saito and walks off. Agnes, who was making a wooden sword, asked Saito to train a little bit. The next morning while they are traveling, Saito sees Tiffania and chases after her. At first she doesn't recognize Saito but after shouting her name a few times, she turns around and hugs him. Louise and Siesta are jealous when they see how big Tifannia's breasts are. The same evening Louise tries to ask who she is, and Saito explains that she saved him during his battle. Out of spite, Louise starts to fondle Tifannia's breasts. But when Saito stops her, Louise runs away and Siesta follows her. After forming a temporary alliance against Tiffania, the two get attacked by Sheffield. Louise tries to protect both of them against Sheffield, but her void magic isn't strong enough. Out of desperation, Louise tries to summon Saito as her familiar again even though it seems impossible. To her surprise, Saito appears and Sheffield was thrown off guard. Due to this, Sheffield retreats and Saito and Louise renew the contract with a kiss. Saito gets the "Gandalfr" runes burned into his hand again.

Tiffania travels back to Tristain with the group. While introducing herself to the Queen, she forced to remove her hat revealing a pair of long, pointed elf ears. Elves are shunned by civilized society, and she explains that she is in fact a half-elf. Her mother was an elf that passed away years earlier, and her father was the archduke of Albion and Henrietta's uncle. As the Queen, Saito, Louise, Agnes, and Tiffania discuss the whereabouts of the other void user(s), Henrietta offers to knight Saito again and he accepts. Henrietta also appoints Siesta as Saito's servant, much to Louise's frustration. Saito, Louise, and Siesta arrive back at the academy by dragon to a huge celebration in Saito's honor lead by the self-proclaimed Knights of Ondine, a group of students at the academy captained by Guiche.

Saito begins training daily with the Knights of Ordine. This leads to him not having as much time to spend with Louise, arousing her jealousy once again. Matters only become worse when Tiffania shows up as a transfer student at the academy. A student named Beatrice, whom is revealed as royalty, becomes suspicious of Tiffania when she refuses to remove her hat. After telling her that she will remove the hat eventually, Tiffania decides to reveal her true identity as a half elf. Upon the revelation, Beatrice proclaims that she has the authority of the Pope and insist that Tiffania be put through a heretical interrogation. She proclaims that if Tiffania believes in the true god, she will be able to step into a pot of boiling water she has had prepared. Saito shows to stop her, but upon hearing from Guiche that Louise would be in trouble he interferes, he bows a begs Beatrice to stop. Upon her refusal, Saito draws his sword against her and the dragon knights in her command. The rest of Knights of Ordine join and a battle ensues. Louise is roused from her sleep by the noise from the battle. She then proceeds to end the battle by exploding everyone, including Saito. Later, Tiffania shows up at Saito's bed and ask him to check her breasts to see if he believes they are real. Louise and Siesta show up in time to witness this, and as a result, Louise proceeds to beat Saito with Siesta's approval.

After the events of the last episode, Saito was forced, in his boxers, to read aloud and sign a pledge admitting that he took advantage of Tiffania in the infirmary. However, he refuses to sign it, insisting that it was she who asked him, and leaves. Upon seeing the shack where Professor Colbert kept his books and other materials, he entered and sadly remembered the teacher's wish to someday visit Saito's world. He apparently starts to doze off, but wakes up after hitting his head on the table. His attention then turns to the piles of gifts being left for Guiche and Reynald, and inquires as to their meaning, in which case, Reynald explains that gifts from the ladies are becoming more common after the fight with the Air Dragon Knights from the previous episode. With love seemingly in the air, Saito remembers the fight with Louise and becomes rather depressed. Upon seeing this, Guiche, Malicorne, and Reynald grow determined to cheer him up. A newcomer in the Knights of Ondine, Gimli, comes up with an idea, and they set about to digging a hole to the women's bathhouse, where they use magic to create a small peephole, bringing Saito along to join them. In the bath, Tiffania explains to Louise that it was she who asked Saito to touch her breasts. This leaves Louise a bit upset over her treatment of him, realizing that she didn't even bother to listen, and fears that he may not come back. However, when Tiffania makes the statement that the two are lovers, Louise immediately shoots that notion down. Saito yells for them to stop peeking at her, and his loud voice gathers the attention of Tabitha, who speaks up. The hole is noticed, and their fun is over. They manage to escape, but are found and swiftly punished by the girls. Saito, however, is saved by Tabitha (as a favor for him feeding her dragon earlier in the episode). When Montmorency comes into the dining hall looking for Guiche, Tabitha hides Saito in a rather provocative manner--by pressing her naked body up against him. When word that Guiche has been found, she heads off, but the sound of whispers gains Tabitha's attention, and she soon passes out from fear of ghosts. The dolls appear and start dancing, and Saito is reminded of the party from the first season. Louise shows up, explaining the nature of the dolls' appearance. She has him admit to being with the others who were peeking, but he explains that he was deceived, half expecting her not to believe him. She believes him, though, and they embrace. However, the embrace comes to an abrupt end when Tabitha wakes up for a brief moment, and once again, Louise gets the wrong idea. He ends up in the same position as in the beginning, only this time the pledge is for him never to touch breasts smaller than Louise's (or anyone else, for that matter). In protest, Siesta grabs Saito's hand and rests it on her breast, and in a rage, Louise blows him up.

It starts off with Siesta at the imp cafe with her uncle and cousin, Jessica, telling her to try harder at getting Saito, eventually giving her a love potion. After the credits, it goes to Saito and Louise’s room where Siesta is cleaning and contemplating using the potion on Saito when Louise comes in dragging Saito who is tied up behind. This causes a fight between Louise and Siesta about the treatment of Saito. Finally, Siesta who believes that she can take better care of Saito than Louise is allowed one hour for that purpose. When the two of them get to Siesta's house she decides they should play newlyweds but after several chances she finally decides to use the potion only to drop it out the window where it is found by Montmorency who imeadietly identifies it as a love potion but accidentally inhales it and the first person she looks at is Louise who has come to check up on Saito, but after Montmorency kisses her it is discovered the potion is more like a virus and it is eventually left for Tiffania to sort out. Tiffania uses a long-forgotten spell to wipe the memories of all those affected by the charm, and Montmorency forgives Siesta for causing the mess, reminding her not to do it again. Tabitha is later confronted by Sheffield, who attempts to sway the young girl by tempting her with promises to save the former's mother.

Siesta, in an effort to win Saito, challenges Louise to a contest. If he can locate Louise at the Seipnir ball, she will relinquish her advances towards him. Louise accepts, telling Saito that if he succeeds, she will allow him to “continue what he started before”. The ball arrives, and each participant takes a turn at the mirror of truth, which transforms him or her into their ideal self. Saito, on the way to the ball, notices a dark shape flying over the academy. Believing Louise to be in danger, he rushes in and begins to search for her. Locating her on the balcony, he has a brief conversation with her before the two kiss. Sheffield then arrives and disrupts the ball, destroying the mirror and reverting everyone to their former selves. Saito then discovers that the girl he kissed is not Louise, but is in fact Princess Henrietta, who had taken Louise's form. She explains that she has always envied Louise, considering her to be much more courageous than herself. She embraces Saito when he attempts to comfort her, and the two almost kiss again. Louise discovers them in this act and runs away crying, ignoring Saito’s attempts to explain. She is confronted and hypnotized by Sheffield who then takes her captive. While going after her, Saito is confronted by Tabitha, who is now in league with Sheffield. After a brief skirmish, Saito defeats Tabitha, but spares her life. He then manages to free Louise from her hypnosis, whereupon the two are surrounded by enemies. They are saved by a sudden wave of fire magic, originating from Colbert and Kirche, riding the dark shape from earlier, which is revealed to be an enormous flying machine.

Colbert is alive. He was saved by Tabitha before death. Using knowledge from the dragons plumage he constructed an air ship with an advanced engine. Louise is still suspicious about what she witnessed between Henrietta and Saito and enlists the help of Siesta and Tiffania to capture Saito and force him (by using magic) to reveal what happened the previous night. Pursed across the ship (under the mistaken impression the magic will remove his clothes) by the increasingly desperate trio he is finally cornered and it is revealed to all about Tabitha's involvement in the previous nights escapade. Saito and Henrietta have difficulty meeting each others eyes throughout the episode but the episode concludes with Louise's resolution to trust Saito while Siesta is still concerned.

The episode begins with the Ondine Knights searching for something when a nude girl drops forn the sky onto Malicorne in the same fashion as when Louise lands on Saito in the opening. Louise kicks Saito in the groin and sends him to the ground then proceeds to ask the girl why she is naked. She introduces herself as Irukukwu. She keeps talking about saving her older sister until Guiche asks her about her older sister, who turns out to be Tabitha. She says how Tabitha was taken as a traitor and stripped of her chevaliar title and how Tabitha's mom was arrested. She continues to tell that Tabitha went to save her mom, but was captured in the process. When Irukuwku asks for help, Malicorne and Saito volunteer promptly, but the others doubt her status as Tabitha's younger sister (on the face that Tabitha is pretty flat-chested and that Irukuwku has huge tits). Irukukwu thinks about obtaining proof and rushes out of the door. The Ondine Knights rush out of the door as well, only to find that Irukukwu has vanished. Not long after, Sylphid appears and testifys for Irukukwu. Saito, Guiche, Malicorn and Louise go to Henrietta to ask for permission to go and rescue Tabitha, which she denies on the grounds that as her personal knights, if Tabitha is rescued by the Ondine Knights, as she is considered a criminal, the rescue could be perceived as an act of aggression on Tristan's part. In response, Saito, Guiche and Malicorn resign as knights in order not to trouble Tristan, and Henrietta responds by having them arrested. Louise asks Henrietta what she thinks of Saito as a man not a chevalier, and Henrietta admits that she is not sure if she has fallen for Saito or simply needs someone to lean on. Louise gives up her position as a noble, declaring that she wants to help Tabitha, to repay her for all the times Tabitha has saved her. Henrietta has no choice but to have her arrested as well. After trying, unsuccessfully, to dig their way out of the prison with spoons, the four get rescued by Kirche and Colbert. Irukukwu reveals that she is really Slyphid, which is a rhyme dragon and capable of transforming into a human form.

Saito and company take refugee in the Charming Fairy Inn while the search for them continues. A plan is created to use the Ostland to fly towards Germinia as a decoy, while Saito goes across the border directly. Scarron provides disguises for them, while Colbert, Seista, Gimli and Reinard proceed to liberate the Ostland. Siesta shows doubts at first of not having any powers but gets encouraged by Saito that she could still help. She hugs him so Louise kicks him in the groin from behind. In Gallia, Joseph and Sheffield uncover a massive object, which Joseph calls Jormungand, covered with pulsing veins and with a single large eye. Posing as a travelling circus, Saito and company cross the border, while Louise broods over no longer being an aristocrat, realising she only has Saito left. Back at the castle, using Siesta as a distraction, Gimli and Reinard take out two guards and they board the Ostland, after dispatching two more groups of guards. Colbert quickly fires up the Ostland, eventually ripping free of the chains that are tying it down. Agnes falls for the ploy, ordering guards to watch the Germinia border. Louise sprains her ankle, and Saito tells her to rely on her, carrying her on his back. She wonders how Saito is so strong, despite being alone in this world. The Ostland is eventually stopped by Tristan dragon knights, and Agnes nearly kills Colbert upon seeing him. Meanwhile, Saito and company arrive in Gallia.

Using her talents at persuasion, Kirche discover that Tabitha is being held in Al Hambra. Upon arriving in Al Hambra, the gang decide upon a plan of attack. Under the pretext of having a show, they will make the soldiers drink alcohol laced with sleeping potion. When Kirche doesn't assign anything to Louise, she gets angry and demands to be given something to do. Kirche reveals that she knows the Louise is a void mage, and apologises for her past behaivor, and invites her over to Germania. Later on, Derflinger advises Saito to say something to her, saying that Void magic is dependant on emotional strength. Saito decides to do so, and finds her posing in front of a mirror in a dancing costume. Louise begins to tempt Saito, and Saito pushes her onto the bed, but they are interrupted by Guiche. In Tristan, Agnes frees Colbert. She saids that she cannot forgive him for burning her village, but has a chance to end the cycle of hatred that would erupt should she kill Colbert. Back in Al Hambra, the Baron wants Louise to attend to him personally, and she agrees, planning to drug his wine, but discovers that the sleeping potion slipped out of her bra. Saito and Tifa discovers the bottle and go to rescue Louise, Tifa using her magic to wipe the Baron's memories. Having drugged all the soldiers, they encounter Bidashal, who easily defeats all their attacks using Counter. Derflinger tells Louise to cast Dispell on him, which she does, allowing Saito to break through Bidashal's Counter. Tifa stops Saito from killing Bidashal, who tells them where Tabitha is and lets them go, and warns them that Joseph is a cold blooded man, and that it wouldn't end there. Tabitha is awakened by Slyphid, and cries upon seeing the gang, even as Sheffield spies on them using her butterfly.

Louise has a nightmare where she loses the ability to cast magic. Awakened, she goes into the forest to attempt to cast explosion. Saito finds Tabitha reading a book, and she began to teach him the words, but Louise interrupts, telling Saito that she can no longer use magic. Tabitha saids that she will protect Saito since Louise is unable to do so. In Tristan, Henrietta dispatches the Ostland and Colbert to rendezvous with Saito, carrying a type of cannon (which seems to be a German Flak88 from WW2), and Agnes offers the assistance of the Musketeer Force. Silently, Colbert hopes the weapon will not be needed. Saito, under Tabitha's guidance, learns to read quickly, while Louise broods over her inability to cast magic. Overhearing Tabitha telling Saito that under the influence of Gandalfr, the heart will experience changes, Louise wonders if Saito loves her because of Gandalfr's influence. Just before crossing the border, a Square-class golem, with Sheffield on its shoulder, lands in front of the carriage and blocking off the route into Tristan. Slyphid and Tabitha take to the air, in order to lead Sheffield away. Guiche, Kirche and Tabitha's attacks prove ineffective against the golem, which is protected by Counter, but they manage to halt the golem's advance with their spells. Saito realises her objective is Louise, and tells her to stay back, but she jumps out of the carriage as Malicorn pulls it back. She is grabbed by the golem, who began to crush her unless she uses her magic. Saito's attacks are easily stopped by Counter, and Louise decides to sacrifice herself for her friends. Saito leaps to attack the golem again, and this time, his attack damages the golem, which releases Louise, and Slyphid saves them in time. Colbert has unloaded the cannon, which Saito examines using his Gandalfr powers, and quickly fires at the golem, but the round is stopped by Counter. Colbert, Kirche and Maricom unleash their most powerful spells, and manage to stop it's advance. Derflinger tells Saito that Dispell needs to be cast on the shells, and Louise refuses, saying she can't do it. Tabitha then kisses Saito, eliciting feelings of intense jealousy in Louise, causing her void powers to be activated again. Louise casts Dispel on the ammunition, which successfully pierces the Counter and destroys the golem. On the Ostland, Louise awakens to see Saito, and asks him if she's okay like this. Saito hugs her, and again declares his love for her, saying he does not love her just because he is Gandalfr. Then Louise kisses Saito while claiming that she has to because he's her familiar. Back in Tristan, Louise kneels before the queen, awaiting punishment for defying her. Henrietta punishes her by awarding her the royal mantle, declaring that Louise is now her sister and second successor to the throne, as well as returning Saito his Chevalier cloak. She then welcomes Tabitha as Princess Charlotte back to Tristan. The ending credits also show Maricom and Guiche wearing their mantles with their school uniforms, signifying that Henrietta has reinstated their noble status. When Louise tries to explode Saito when she sees Tabitha holding onto Saito, Sylphid grabs Saito and escapes with Tabitha.