Miike Naeko of the MPD Transportation Department goes to karaoke with her colleagues Yagi Shiori and Momosaki Toko. On the way home, Momosaki is attacked once she's alone, and her body is discovered the next day. One week earlier, Momosaki and Yagi arrested Aono Kengo, Akamine Manji, and Shiroyama Yuzo for traffic violations and got into a fierce argument, and the police believe it may be related to this case. Meanwhile Yagi goes to visit a certain individual.