As part of a psychological research project, you and nineteen other recruits will be divided up into prisoners and guards. In a controlled penitentiary-like environment, "Prisoners" are incarcerated and ordered to obey the rules, "Guards" are instructed to keep order.
You will be thrown head-first into a two-week long examination of the effects of assigned roles, power and control, and you won't be the same when it's over. But it's just a simulation. Or is it? Moritz Bleibtreu (from "Run Lola Run" and one of Germany's biggest stars) is Tarek (A.K.A. Prisoner # 77), an ex-journalist intrigued by the idea of going undercover for this experiment, positive the ensuing interactions will provide his editor with a fascinating story. At first, the prisoners treat their roles with detached humor and playfulness, and the guards treat theirs with nervous unease.
But within hours, small conflicts and petty disputes force all twenty men deeper into their assigned roles. As these trivial skirmishes quickly escalate, the guards must explore any possible means to keep the prisoners in line.