As Chirico and his friends go to work patching up derelict vehicles, a familiar face looks down on Sunsa from orbit: Rochina. Now in command of a Leslion-class Balarant Battleship, he has crossed both the nonagresssion zone and his allegiance to Melkia in order to find Chirico again. Rochina's ship descend on the abandoned supply station, and Chirico's group is quickly overwhelmed and taken captive. Chirico is taken directly to Rochina, who offers the release of his friends if Chirico will consent to face Ypsilon again. Chirico questions Rochina about who he really is. Rochina's only answer is that he is a man from the kingdom of heaven.

Captain Futtor discusses the situation with Arron and Gurran aboard the Teltain. They have not heard from Ypsilon since the raid on Zophie's fortress, but they are sure he will go after Chirico despite the Balarant presence. When that happens, the Secret Society must be ready to recover him.

Chirico agrees to Rochina's terms, and is freed to prepare for the battle. He doesn't have long to wait - Ypsilon and his small platoon launch an attack on the Balarant landing party and fight their way quickly inside the perimeter. Rochina orders all ships to launch, and Chirico is left behind in a Fatty to face his enemy. In short order, they find each other in an empty chamber deep inside the supply station. Once again, they draw their weapons and prepare to engage. Rochina arrives to watch with Fyana in tow, but there is nothing that can be done to stop the fight now.

"His will to fight was practically a madness. But, as opposed to him, my heart didn't burn. the thing that drove me on was an almost pitiful craving for battle that raged within me."

Chirico and Ypsilon unleash heavy fire, with Ypsilon pausing only to eliminate anyone who threatens to interfere in their battle. Suddenly the entire room starts to shake, and the floor drops out from under their ATs - their battle has ignited the ammo dump! Plummeting helplessly, they disappear into a deep shaft, and Rochina managed to escape with Fyana as the entire building crumbles.

Landing relatively intact, Chirico gets the upper hand against Ypsilon, but does not choose to kill his foe. Instead, he begins to dig himself out and suggests they work together to survive.

On the surface, Rochina orders his men to begin an excavation and recover Chirico. He discusses the situation with Fyana, who suspects that he is hiding the answer to a key question: how has Chirico, an ordinary human, lasted so long against Ypsilon, a Perfect Soldier?

Similar questions burn through Ypsilon's mind as he and Chirico make their way toward the surface. The PS angrily declares himself a superior being, and that he belongs with Proto-One. Chirico corrects him on the name, and Ypsilon demands to know why he calls her Fyana - a question Chirico is unable to answer. Finally, when they reach the upper limits of the shaft, Ypsilon admits that they are alike in one respect; Chirico can fight as well as he can...but Ypsilon will eventually kill him.

On that note, the Balarant excavation team finally breaks through from above and rescues Chirico. Ypsilon slips away just in time to join up with a rescue team from the Teltain, and they fight their way free. Chirico is taken to Rochina, who demands that he be ready to fight Ypsilon again. In return, Rochina orders Gotho, Vanilla, and Coconna flown out of danger.

"It seemed Rochina had kept his promise. My final battle with Ypsilon. The time was fast approaching. Will I survive it, or will he? And if I do survive, what then?"