Miike Naeko of the MPD Transportation Department is concerned about the lack of development in her romantic relationship with Detective Chiba and goes to karaoke with her colleagues Yagi Shiori and Momosaki Toko to sing away her sorrows. While there, Yagi and Momosaki learn that both of them have been followed by someone recently. Momosaki sends off the drunk Naeko and her caretaker Yagi. Once she's alone, a suspicious man begins talking to her.

MPD Traffic Department members Momosaki Toko and Yagi Shiori are murdered one after another. Detective Sato and the rest of the police begin canvassing the neighborhood where Yagi fell. Miyamoto Yumi arrives on the scene and offers a certain tip... In order to acquire more hints, Yumi calls Miike Naeko, who went to karaoke with her colleagues the other day. All the while, a suspicious man listens in on her conversation with Naeko.