One morning, a junior-high student, Kobayashi, wakes up and finds himself in his classroom with his homeroom teacher's body. In his hand is a murder weapon. A high-school detective, Akechi, is called in to assist the police to solve the case.

Kobayashi has been arrested. It seems that he's been charged with additional crimes. Before the police take him away, he whispers something to Hashiba. What will happen to him? Who is the real killer? Will he be able to solve this crime?

Nine girls have been abducted in two months and the police suspect that Shadow-Man, a master of disguise and gentleman thief, might be the kidnapper. When Akechi declines to take part in this case, Kobayashi asks if he can investigate it instead.

A man who calls himself Twenty Faces commits a series of murders. His victims are all criminals who have escaped justice and have not atoned for their crimes. Before he kills, he posts a message on the Internet to explain who he's going to kill.

In an interrogation room, Twenty Faces reveals what made him decide to operate outside of the law to punish criminals.

Akechi's chaotic day starts when Kobayashi finds an abandoned kitten at the front door of the Akechi Detective Agency. Kobayashi wants to keep the kitten, but Akechi does not approve. Then another incident occurs. This time, Shadow-Man is involved.