Inside Phi Up, an American college fraternity, six pledges—Bonner Todd Eastland, Goodman David Neal Evans, Cagle Craig Derrick, Silvera, Bodine Dennis Sullivan, and Zahn James Davies—face Hell Week, a grueling three-day initiation inside the brotherhood’s house. On the eve of Hell Week, a disturbing incident shakes the men: Dan Arthur Lundquist, appearing unstable, stabs Rex during a mental breakdown. The rest rush Rex to the hospital, and Chip urges the pledges to keep the episode quiet, warning them not to tell anyone else about what happened.
Over the first two days, the pledges are subjected to increasingly painful and humiliating hazing rituals. They endure tasks like eating live worms and raw eggs and even carrying cherries with their buttocks, among a string of derisive tests meant to prove their loyalty and resilience to the fraternity. Meanwhile, Wendy—the girlfriend of Rex—drops a bombshell to Bonner: the Rex incident was staged, and Dan is merely pretending to be crazy as part of a calculated test of the pledges’ loyalty. The story deepens when Bonner’s mother arrives for a private conversation with her son and reveals a haunting piece of the house’s history.
In 1969, Sidney Snyder, who was then involved with Bonner’s mother, died in a hazing gone tragically wrong. The hazing involved lying in a tub filled with cornflakes, coffee grounds, vinegar, and soda, but it turned deadly when muriatic acid was mistakenly added, leaving Sidney badly burned and fatally injured. This brutal memory casts a long shadow over the present, adding a layer of ominous history to the ritualistic atmosphere of Phi Up.
On the final day, J.D. escorts the pledges to the basement for a grim lecture on the supposed history of college fraternities. It is then that Sidney Snyder’s ghost materializes and begins to terrorize the house, starting with the murder of Tom in an upstairs bathroom. Dan, now seemingly possessed by Sidney, murders Chip as he investigates, then proceeds to kill two sorority girls who were assisting Wendy in preparing food for the brothers and pledges.
J.D., frustrated by Dan’s hysterical laughter, confronts him alone only to be overpowered and knocked unconscious, then tied to a shelf. Wendy returns from shopping and discovers one of the murdered girls, rushing to the basement to warn the pledges. Sidney’s specter bursts from Dan’s body and sins against J.D. by detonating a cherry bomb in his underwear, a noise that echoes through the basement and draws everyone’s attention.
Sidney continues his assault, appearing in the basement to murder Cagle and then destroying Silvera by causing a fatal explosion of his stomach. The survivors scramble for a path to safety as Zahn tries to call the police, but his warnings are dismissed. Sidney then claims Zahn’s life before moving on to kill Goodman and Bodine. With Bonner and Wendy the last remaining survivors, Sidney confronts them directly. When Bonner speaks his own name aloud to Sidney, the ghost—who is strongly implied to be Bonner’s late father—pauses and touches his shoulder, explaining that his killings were meant to shield Bonner from the fraternity’s negative influence before fading away.
Some time later, Rex is shown lying in a bunk with another girl, lamenting that Wendy left him for Bonner. The two lovers don’t notice Sidney creeping into the room, sword in hand, as he hides in the shadows. He positions himself beneath the couple, and then the camera lingers on Sidney’s menacing smile as he looks toward the audience, leaving a chilling final note to linger beyond the scene.
