Based on the first volume of the light novel, it greatly condenses the story.

The setting is a rural city in which a kidnapping and a series of murders are happening simultaneously, where there was also a kidnapping 8 years ago. The victims, the compulsive liar "Mii-kun" (the narrator), and "Maa-chan" (Misono Mayu) reunite and start living together, despite of the fact that the kidnapped children were in Mayu's apartment...