From Kenta Fukasaku (Battle Royale) comes a twisted tale about the lives and deaths of several high schoolers. They receive a message from their friend Asuka telling them to go back to their classroom in the middle of the night. This ordinarily wouldn’t be an issue, except for the fact that Asuka was supposed to have committed suicide. The group does as they are told, only to run into a killer wearing a bloody rat mask seeking revenge. Will they be able to uncover the identity of their mystery murderer and survive until the next morning?