Ren Fujii is an ordinary student who recently got into a fistfight with his former best friend, causing him to end their friendship. However, with the assistance of his childhood friend, Kasumi Ayase, and his upperclassman, Rea Himuro, he is slowly getting back to his regular school routine. Then, a series of brutal murders begins to hit their city, in which the victims are decapitated. Oddly, at the same time, Ren starts having terrifying nightmares of being beheaded by a guillotine. But these are merely a prelude to the painful and frightening battles that lie ahead.