A strange announcement suddenly appeared on the calm university campus. A guy who called himself D said that he would perform a grand performance for the teachers and students of the school. The students' conversation immediately focused on this announcement. Is it a club's gimmick to impress people, is it a prank by a student, or is there really something that D has prepared? Just when everyone was guessing the reason for the performance, something unexpected happened. A terrible thing happened in the auditorium preparing for the school speech final. The top judge of the final was killed in a special way. After that, a series of terrible things happened. Can college student detective Li Mohan find the truth of the matter? And what is the secret hidden in his heart?