One day, the protagonist, Takuto Urashima, saves his classmate, Otohime Fujimiya, from being involved in a traffic accident, but dies and falls into hell. However, in hell, a "hostage exchange game" is being held, with a chance to come back to life... Participants are divided into two roles, master and slave, and each master is given one slave on the first playthrough. Luckily, Takuto is chosen to play the game as a master, but the person chosen to be Urashima's slave is his classmate, Otohime Fujimiya, whom he was supposed to have saved...!?