Dr. Archaleta leads a controversial psychological study that gathers volunteers, among them Travis, a ready-to-defy anti‑war protester, and Michael Barris, a 42‑year‑old man living with a domineering mother. After interviews measure responses to scenes of violence, a carefully selected group is transported to an isolated, prison‑like facility where 24/7 cameras capture every moment. The participants are split into six guards and twenty prisoners, and they are referred to only by numbers. Travis is assigned as prisoner #77, while Barris serves as a guard, setting the stage for a tense power struggle from the very start.
The prisoners must eat three meals daily, enjoy thirty minutes of recreation, stay within designated areas, and avoid addressing guards unless spoken to first. The guards, in turn, are tasked with enforcing obedience and handling transgressions within half an hour. Archaleta stresses that the experiment will end at the first sign of violence or if a participant quits, and if the rules hold for two weeks, each man will receive $14,000. The arrangement promises a dramatic test of boundaries, control, and human behavior under pressure.
Travis’s cellmates include Benjy, a graphic novelist, Benjamin With Bødker, and Nix, a former member of the Aryan Brotherhood who has done time before. Barris grows increasingly wary of potential violence among guards and prisoners, and he begins to push for more aggressive means to secure obedience. Yet his fear of losing control only fuels his own brutality. As the guards tighten their grip, Barris gradually slides into a more sadistic role, pressing other guards to shoulder the growing sense of power he wields.
Realizing that the defiant Travis is affecting the mood of the prisoners, Barris orders drastic measures to suppress dissent. He has Travis abducted, shaves his head, and subjects him to humiliation in ways that cross the line. When a fellow guard, Bosch, voices dissent, Barris pressures him to stay the course, justifying the actions as necessary to maintain order. The situation spirals as fear, anger, and resentment bubble to the surface, and the line between discipline and cruelty begins to blur.
Travis soon learns that Benjy, who is already ill, has been hiding his need for insulin, hoping that diet alone could manage his diabetes. Bosch tries to help, but his attempt is thwarted by the guards. Barris ultimately provides Benjy’s insulin, yet the act is turned into a weapon as he orders the guards to beat Bosch and then forces Travis to clean the prison toilets. When Travis taunts Barris, the guards shove his head into a toilet, nearly drowning him and revealing just how far the system has deteriorated.
One morning during roll call, Travis strips to protest the conditions, and the other prisoners join his display of defiance. He climbs to a camera and demands release, but the guards choke him. When Benjy intercedes to defend Travis, Barris bludgeons him into silence. The guards seal Travis in an old boiler pipe overnight, strip the others of their possessions, and handcuff each man across the cell doors, escalating the cruelty to a new extreme.
Inside the boiler, Travis discovers a hidden infrared camera and his despair shifts to determined resolve. He manages to escape during a guard’s attempt to rape a prisoner, and he and the other inmates overpower the guard. They free the remaining prisoners, but the grim toll becomes clear when Benjy is found dead from a head injury. Travis leads a charge against the guards, chasing them through the building as the guards try to flee the chaos.
Barriss clings to power, attempting to keep the guards from quitting as the fortress-like structure trembles with violence. A brutal confrontation ensues as the remaining guards try to lift the garage door to escape, and Barris fights to hold them in. Travis meets Barris face to face, their struggle turning visceral: Barris lunges with a knife, but Travis stops the blade with his bare hand. The shock of his own action renders Barris unable to continue, and he allows Travis to beat him to the ground. The door finally opens, signaling the end of the experiment and the start of whatever aftermath awaits.
As the group steps into bright sunlight, they sit in stunned silence on the grass. News audio snippets reveal that Archaleta is being tried for manslaughter in Benjy’s death. With the experiment behind him and his payment in hand, Travis leaves for India to reunite with his girlfriend, stepping away from the darkness of the test toward whatever future lies ahead.
