A popular English teacher, Mizuguchi Risako has been kidnapped three days before the high school's graduation ceremony. Four high school seniors received a mysterious challenge letter, asking them to solve the mystery of the kidnapping case within 72 hours. The four students are Kurokawa Yoshiki, his childhood friend Takahata Ayane, sports all-rounder Ogita Junpei, and school's beauty contest winner Komatsu Mio. The four students were wondering why they're the only ones who received the letter, but later gradually found out the "other face" of Mizuguchi which she has been hiding.
Yuki Inoue
Hiyori Sakurada
Jun Nishiyama
Ayaka Konno
Karen Takizawa
Akiyoshi Nakao
Mansaku Ikeuchi
Tatsunari Kimura
Nobuko Sendo
Hiromitsu Kitayama
Rie Minemura
Rika Adachi
Kanro Morita
Tomoaki Honma
Nao Takahashi
Ichika Osaki
Moe Edamoto
Hitomi Kanno
Maki Hironaka
Yusuke Tooyama
Yuuki Shimazaki