Takagi Masaru (Mamiya Shotaro), the leader of Class 6-1, unearths a time capsule for the first time in 22 years at a class reunion. Inside is a yearbook in which six students have been blacked out. The six students, who share a grudge against classmate Saruhashi Sonoko (Araki Yuko), become the targets. The next day, a series of suspicious deaths of classmates begin, and Takagi, one of the targets, is terrified. Is Sonoko the culprit? Or...? The suspect is a classmate, but who is the real culprit? A nonstop mystery that will have you thinking begins!