Yuito's memory of his childhood savior returns. While off duty, Yuito and Nagi run into Naomi and Kasane. Something is afoot in Seiran, but is it related to Karen's agenda? The Seto and Kyoka platoons train, and then scramble to intercept the Others.

Something goes horribly wrong with Naomi, leaving her comrades dazed and confused. It's clear there is more to it when they're told to keep quiet. Kasane divulges a shocking secret to Yuito, and the Seto and Kyoka platoons face an unexpected enemy.

Yuito begins a new journey, and Kasane is tasked with a new mission. Promotions and new challenges await their comrades. But as they each go their separate ways, will anyone remember Karen's sacrifice or that he even existed?