A horrible murder has been committed on the grounds of Nankai Academy. Professor Yuko, one of the schools most popular teachers, died when she was pushed off of the roof of one of the schools buildings. Her death has left her students with feelings of confusion, pain, and above all else anger. Four of her male students, Masayoshi, Daisuke, Mitsuru and Shinya, are determined to uncover the truth. They soon discover an important clue: Professor Yukos planner had been marked on the very night she was killed marked with the names of seven girls.