Aito Eyama is constantly subjected to bullying from his classmates, enduring both verbal and physical abuse. However, his life takes an unexpected turn after he receives an invitation to participate in the "Captivity Game", where the winner is offered an incredible sum of money. In this game, Eyama must become the captor and keep one individual imprisoned for a month. The only choice he has is his principal bully, Aya Kirishima. The rules of the game are clear: Eyama can do anything he wants with his captive, but killing them is strictly prohibited. To win the game, he must ensure his identity remains a secret, and the game provides everything he needs, including a secluded cell, supplies, and protection from the law. As Eyama inflicts his revenge on Aya, he soon realizes that there are other captors with their own hidden agenda. Meanwhile, Aya refuses to remain a passive captive and does everything within her power to escape. In doing so, her actions may awaken a dark side of Eyama that has long been suppressed, and that yearns to be unleashed.