Left Behind

Left Behind (とりのこされて, Torinokosarete) is the seventh episode of the anime series.

Summary
Sousuke argues with his replacement, Agent Wraith, about the mission to protect Chidori. Chidori wonders why Sousuke has not been attending classes in days and starts to become worried. When she needs to see him after a chance encounter with Amalgam agent Xia Yu Lan, she finds his apartment vacant and he has disappeared.