Guessing Kuroshima's stalker, Uchiyama, may have been bugging Kuroshima's room, Shota raids Uchiyama's place. Shota finds a disturbing and shocking confession that Uchiyama made by video prior to his death.
Minami suspects Tamiya is the killer of a five-year-old unsolved murder case and questions him. Shota enters Minami's unit and upon seeing a large number of documents in the room, realizes something is up and rushes out of the place.
Kuroshima is likely to be the mastermind of the murder game based on the AI analysis. Shota finds a new clue from the puzzle Nana left, and decides on a plan to lure the mastermind out of hiding.
Shota is attacked by Nikaido and loses consciousness. When he wakes up, he finds Kuroshima also restrained. The whole swap murder game is finally revealed!