A brief history of the Harmonic Unification War is introduced, but hold that: Tori is having a "pre pop the question" get together with his class! How ill he confess his love to this mysterious girl? Meanwhile, Masazumi Honda contemplates the way her life has turned out thus far, and just what she can do to change it.

The students make preparations for a party by Toori's request while Masazumi hears from her father about the tragedy that befell Horizon and Toori 10 years before. Meanwhile the Musashi is approached by ships from K.P.A. Italia and Trés España, two of the Harmonic Divine States with unknown intentions.

Trouble is afoot. Allegiances will be tested, friendships broken, and a true power will awaken. Who will walk away the victor? Only time will tell, and in this world, time is all that matters.

Don't come to a super powered knife fight without your Armor of Deadly Sins. As the platonic reactors begin hitting critical mass, one warrior stands tall to stop a madman bent on destroying all of Mikawa, while another equally skilled warrior stands in his way. Will he succeed, or will Mikawa burn away in the night?

With Horizon detained and expected to commit suicide, the students of Class 3 - Plum must decide what to make of the situation. Tensions are sky high, and making the wrong move could spell disaster for Musashi's people.

A best of three battle will decide the road that Ariadust Academy will take in the upcoming war. 3 representatives from each side will do battle, in any way desired, and the losers will bow to the victorious!

The war of words begins. Masazumi goes head to head against Tori in the final leg of the bet of three battle to determine the fate of Horizon Ariadust. A surprise entrant in the debate makes his presence known, however, and Masazumi must defend her new position as best she can.

The time for talking is over. Blades are unsheathed and ready to strike, as both sides decide that a quicker solution to the Horizon problem must be reached. As both the Testament Union and the Musashi representatives prepare for the worst, new information is revealed that can potentially change everything.

In order to save Horizon, the newly elected Chancellor Tori must take his army through the Testament Union's best ground defenses. Meanwhile, the battle over the skies will be determined by a God of War and two witches in hiding. Who will reign supreme over ground and air, and will they get there in time to save Horizon?

With the Testament Union breathing down their necks, Tori and the rest are at their wits' end now that the High Pope has unveiled his trump card: The Armor of Deadly Sins - Lust. With it's incredible defensive capabilities, there's only one thing Tori can do to stop him: the impossible.

Futayo continues her battle with Muneshige and arises victorious. Tori makes it to Horizon, but she doesn’t want to be rescued. Tori must not only convince her to leave with him, but also figure out how to defeat the Disintegration Wall.

The class of 3-Plum heaves a sigh of relief after Horizon Ariadust, the automaton P-01s, and Toori Aoi finally reunite for the first time.