The body of Otani Noriyo (Akama Mariko), the homeroom teacher of Takagi Masaru (Mamiya Shotaro) and Saruhashi Sonoko (Araki Yuko), is discovered. Not wanting to involve anyone further, Takagi pushes away his former classmates Tsuchiya Yuki (Gouriki Ayame) and Toyokawa Kengo (Inaba Yuto), who want to help, and he also becomes hostile towards Koyama Takahiro (Morimoto Shintaro), leaving him isolated. Meanwhile, an unexpected "truth" is discovered in the room of Hatachi Taisuke (Mori Yusaku), who suddenly disappears.
