Akari and her boyfriend Hiroshi take part in a part-time university experiment: "Happy couples of five years or more become jailors and prisoners. Just how will it change them mentally?". While all five couples started out well, they get swallowed up by the strange prison-like atmosphere. Under the pretext of punishment, the male jailors start sexually assaulting the female prisoners! What will become of Akari and Hiroshi!?