Aito Eyama, a victim of frequent bullying, is troubled by his peers' insults and beatings. However, via a fortunate turn of events, he obtains an odd invitation to the "Captivity Game," where winning guarantees incredible money. To take part, he must play the role of captor and select one victim to jail for a month. Aya Kirishima, the ringleader of his bullies and the source of all his anguish, is Eyama's sole option. The rules of the game are simple: the jailer may do whatever they want with their captive, even murder; but, in order to win, the captor's identity must be kept disguised. Exemption from the law, isolation in a cell, and monies to acquire supplies—all of the required tools are supplied.