A terrible murder was committed on the grounds of Nankai Academy. Professor Yuko, one of the school's most popular teachers, died when she was pushed off the roof of one of the school buildings. Her death left her students with feelings of confusion, pain, and, above all anger. Four of her male students, Masaesi, Daisuke, Mitsuru, and Shinya, are determined to uncover the truth. They soon discover an important clue: Professor Yuko's planner was marked that very night she was murdered ... marked with the names of the seven girls. With this evidence, the boys begin their research ... and they will use whatever method is necessary to find the murderer. Through rape, manipulation and torture, they will uncover important details, but piercing the mystery will not be easy. And the longer their search relies on, the more they feel its overtaken by their darkest desires... Will they ever discover the truth behind Yuko's death?