The 42 students of the 3rd B of Shiroiwa College were chosen to participate in the "program", a game intended to experiment with murder; the first day just passed that, already, half of the participants are missing the call. They were, for the most part, victims of comrades determined to participate in the game in order to survive. Among these assassins is Mitsuko Soma, a girl with fascinating beauty, who releases a real aura. Her victims were deceived by her beauty and apparent fragility. How can she kill so easily? Will someone be able to stop her murderous madness?