Kindaichi Hajime is a high school student and a private detective with an IQ of 180. He solves murder cases that are riddled with difficult clues. Kindaichi Hajime works with his childhood friend Nanase Miyuki and Kenmochi Isamu. Kenmochi Isamu is now the chief inspector of the Tokyo Metropolitan Police Department.
With graduation 10 days away, homeroom teacher Hiiragi gathered all 29 students of class 3-A and proclaims them his hostages. His last lesson regards the death of a student that passed away a few months before. Nobody will be able to graduate until the truth is known.