Yuu feels trapped in his hometown. He decides to go to Tokyo and visit his girlfriend, Megumi. Yuu tells her that he wants to live with her in Tokyo, but she is confused by his sudden visit. They end up having an argument. Yuu doesn't have a place to stay in Tokyo, and he ends up staying at a cheap sharehouse named Hakobune. Other people staying there include Yamaguchi, Maru, Yoshiko, Goro, and Kirishima. During his first night there, Yuu sees Yamaguchi and Maru having an argument.
The next day, Yamaguchi seems to have disappeared altogether. Yuu gets a strange feeling because he remembers Yamaguchi stating his intentions to stay there for another six months. Soon, Yuu suspects some of the creepy residents at the sharehouse are responsible for unconscionably evil acts.
The events of the series of the offender revolve in a framework of suspense and excitement in separate episodes, where each episode is investigated in a different crime by searching for clues and evidence in order to reach the perpetrator of each crime.