An unpopular idol, Kurobara Junko, pretends to be innocent, but in reality, she is an absurd girl who is jealous of her rival. She volunteers to work as traffic safety and security awareness in a parade to increase her popularity, but ends up discovering a murder scene and being accused of being a serial murderer who called himself a "justice". She then works with police detective Todo Shusaku to solve the murder and clear her name.