Kangoku Jikken

Aito Eyama, a high school student enduring daily bullying, receives a mysterious letter on the final day of school before summer break. The letter invites him to participate in a "prison game," where participants can imprison someone of their choice for a month. During this time, the Player may do anything to their Partner as long as they do not kill them. If the Player's identity remains undisclosed, they are eligible to receive a substantial amount of money.