The film opens with a striking scene of a two-story white house in the 1960s. Letters flash across the screen, setting the time period, as a vintage car pulls into the driveway. A middle-aged man steps out and rushes to the front door, where a woman answers his anxious knock. He confronts her, demanding to know if she has told anyone about something significant. The woman admits that she mentioned it to her husband because she found the name amusing. Apologizing for his intensity, the man returns to his car, retrieves a shotgun from the backseat, and approaches the door once again. In a panic, the woman slams the door shut, but he retaliates by shooting through it, creating a gaping hole.
The story then shifts to a train at night, as the camera pans to reveal various debris scattered along its path, including a broken picture frame and bloodied clothes. Returning to the middle-aged man, we see him in a living room, having just shot another man who is helplessly trying to crawl away and calls out for his wife. With a chorus of fading train sounds and ephemeral lights flickering across the wall, the man bellows in defiance, "You’re not gonna get me!" before delivering a fatal shot to his victim.
Suddenly, he notices two women outside his window, and when he recognizes them, he pursues them as they flee towards a nearby house. "Who did you tell?!" he bellows in desperation as he follows them inside, leading to a crescendo of gunfire before the scene fades.
Moving to the present day, we meet three college students: Elliott, his girlfriend Sasha, and their friend John, who arrive at a seemingly perfect rental house. They explore the unfurnished rooms, initially feeling excited—though Sasha can't shake an unsettling feeling about the place. As the evening falls, Elliott and Sasha settle into their bedroom, now furnished, where he works on a paper. Sasha finds a peculiar love letter from him, made from cut-out newspaper letters. When a strange noise catches her attention, she opens the attic door, uncertain, just as the door to their bedroom slams shut, leaving her calling out to Elliott, who is nowhere to be found.
At a party later, Elliott’s niece, Alice, wanders the house, drawn to the eerie sounds of a coin rolling. She opens the attic door and surprisingly encounters a haunting wolf head behind her before running back to the festivities. Disturbed by her discovery, Alice shares her findings with Elliott. Amid the confusion, Elliott discovers a coin and is drawn to the mysterious writing inside an old dresser: "Don't Say It, Don't Think It." This revelation leads him to investigate the legend of The Bye Bye Man.
During a séance led by Kim, a girl whom John is enamored with, the group inadvertently triggers a sinister presence when they utter the name The Bye Bye Man. Darkness envelops them, leaving them shaken. As the night progresses, eerie occurrences torment Elliott and his companions, leading to terrifying realizations about the house's dark history and its connection to the Bye Bye Man.
As tensions rise, Elliott and Sasha's relationship strains under the weight of hallucinations and dread, particularly when Elliott grapples with the implications of the Bye Bye Man's curse. Their search for the house's origins uncovers a tale of murder and horror connected to the Redmon family, leading Elliott to confront Mrs. Redmon, who reveals her harrowing past with the Bye Bye Man and the consequences of speaking his name.
In a tragic series of events, Elliott's struggles against this malevolent entity culminate in a harrowing climax marked by hallucinations, desperation, and violent twists. "The cycle must end," Mrs. Redmon implores, leaving Elliott to confront a nightmarish reality that spirals out of control. Ultimately, Elliott finds himself embroiled in a tragic descent into madness, where he must fight to protect his loved ones from the fate of the Bye Bye Man as the horrifying truth unfolds—a haunting legacy that can't be easily escaped.
