Kenmochi presents Hajime with another case. A computer teacher named Nanako Segawa is found dead in a park. Yuri Mishima, a student from the computer school is arrested for the murder, but Hajime thinks that this is an exchange murder, and there is a mastermind behind the killing. There are three suspects who also use Yuri's computer, and none have adequate alibis. After examining the computer room and the evidence, Hajime believes he knows the culprit...