- Natsumi Yukihira has the highest arrest rate and is the most beautiful detective in the Tokyo Metropolitan Police Department. Her partner is a rookie cop, Kazuyuki Ando.
One night, a high school girl and a businessman are killed. Shortly after, a third body is found, along with a bookmark that has a mysterious message: “Who’s unfair?” A manuscript titled “A Mystery Novel—Volume 1” is then sent to the police and press. Written in it, are details which only the murderer is capable of knowing, an announcement to kill its next victim, and an unbelievable demand: “If you want the killing to stop, make a successful bid on the next book.” Natsumi must tackle a brutal killer that commits murder exactly like the novel.