Mystery Club Girl's Incident Book

The reasoning department of Caiyang No. 1 Middle School is completely different from other clubs. Although it is in the name of a club, it is actually a commission to solve the mystery. A yandere girl who sends an anonymous letter with an unknown purpose, a music classroom that turns on its own lights every ten o'clock in the evening, a strange story that a girl in red will have her hair cut short the next day, the sound of classical music coming from the locked library, and a challenger who claims that the puzzles he set will not be solved... Every day with the director of the reasoning department, Xia Lan, constantly solving incidents is the daily life of the reasoning department!