After arriving at Zuellni Academic City, mysterious Layfon makes quite an impression - and is quickly forced into joining the 17th Platoon of the Military Arts Department.

Zuellni falls into a massive nest of Contaminoids! As Nina leads the Military Arts students into battle, Layfon stays behind, convinced it’s a suicide mission. If he doesn’t join the fight, all could be lost.

The 17th and 5th Platoons must work together to investigate a city left in ruins by Contaminoids. During the mission, Gorneo shocks Nina when he reveals information about Layfon’s secret past.

New information shared by Gorneo forces Nina to consider Layfon’s future with the 17th Platoon. Meanwhile, Leerin finds herself in serious danger as a direct result of Layfon’s past.

As Layfon and the others search desperately for the missing Nina, the 17th Platoon is caught in an ambush perpetrated by a villain who has been lurking very nearby.

When the Fallen One possesses Savalis, Layfon might not have the power to survive. Everything he holds dear is on the line - and the fate of Zuellni is in his hands.