From Renta!:

Shikiyama is looking to make some easy money when he finds an ad for a university experiment: "$6,000 for a one-week stay." Not even knowing what the work entails, he finds it rather suspicious, but the temptation of the paycheck is too much to resist, and the young, handsome man signs up. On the day of the experiment, he learns the particulars-the group is divided into prisoners and guards in a "mock prison." Shikiyama finds himself playing the role of a prisoner, and, though he thought he could get away with slacking, he ends up a target for the guards. Soon, he is stuck living the life of a real prisoner! Can Shikiyama handle the many indignities thrust upon him!? And what will be the result of the week-long experiment!? This is real psycho BL horror.