A cynical 17-year-old boy, Nonomiya, spends day after day wasting away from boredom. Only watching people—and his own imagination—somehow entertains his inquisitive mind. But on one fateful day he finds a bag forgotten on a desk, belonging to the beautiful top student Yoko Tsukimori. And he sees a paper sticking out of it with the unexpected title “Murder Recipe.” His unhealthy curiosity turns out to be impossible to resist. Yet the paper contains only vague drafts of abstract murder plans, based more on luck than on calculation. And the next day her father dies—an accident…