Legend has it that in Takada Chinatsu's new town, there are demons known as Tsumitsuki who take over a person's sense of guilt for their sins. The possession takes a toll on the individual's physical and mental well-being as the demon takes over. When Takada observes her friend's peculiar behavior, Kuroe, her schoolmate, intervenes to assist, but his actual intentions remain unknown as he conceals his true identity.