Dennis is a 30-year-old man living with a disability who has endured nightmares since childhood. One persistent dream follows him and his mother into a carnival ride that feels oddly underwhelming, until a chilling warning reminds him that the ride isn’t over. As an adult, the nightmare returns in an even more troubling form: a living demon known as the Cadaver clamps a zipper onto his back and slips inside his body. In an attempt to understand what’s haunting him, Dennis discovers a hidden cellar room that houses a mirror he believes is connected to the Cadaver, and he begins speaking to his reflection, which seems to answer back.
Dennis’s brother, John, carries his own burdens. His girlfriend Lydia pushes for marriage, but John is hesitant, especially because she worries about Dennis. A social worker named Mildy Torres arrives with concerns that Dennis might need to be taken away, which strains John’s sense of responsibility and protection. The nightmares continue, and the reflection whispers that to drive the Cadaver out, they must start by killing animals. This troubling idea leads Dennis to work in the secret cellar, where John notices odd hours and unusual footage of taxidermy and embalming.
The danger escalates when Dennis begins killing children, and his reflection grows more competent, hinting that it was the one behind the nightmares all along and that there may be more killing to come. In the midst of these horrors, Dennis meets Susan, a coworker at his favorite ice cream shop, whom he admires and hopes to date. The conversation is awkward and she turns him down, leaving him hurt. Later, Dennis’s return to the shop is even more troubling as he confronts Susan in a terrifying moment, and she flees only to be struck by a moving vehicle outside.
John and Lydia take Dennis to his beloved restaurant, where an unsettling incident occurs in the bathroom—Dennis appears to kill a man without hesitation, a moment that haunts him afterward. Desperate to silence the mirror, Dennis tries to destroy the very object that anchors the Cadaver to him, but the reflection pushes him inside the mirror and switches places, taking on the “real” Dennis’s identity.
One night, after a long outing, John and Lydia discover that they can no longer recognize anyone around them, a clue that Dennis has already claimed more victims. Torres arrives with two officers, but Dennis eliminates them all. John then reveals a long-buried secret: Dennis was a child prodigy whose work had once appeared in newspapers. In a moment of rage, John punched Dennis, who fell down the stairs and, when he woke up, experienced a diminished mental state. Guilt lingers for John as Lydia tries to help, and Pete, a friend of John’s, later reveals that the taxidermy and embalming tapes belong to Dennis and calls the police.
Lydia confronts Dennis at home, but he stabs her in a brutal act and removes her insides. John follows to the cellar, where Dennis stages a theatrical ventriloquist act with a stuffed Lydia, trapping John in a chair with a spotlight on him. The haunting tableau reveals a diorama of previous victims, leaving John unsure what is real as more bodies appear. Overwhelmed, John shoots himself, while a Cadaver-Spider hybrid appears to attack Dennis, only to reveal that the police are actually restraining him as they drag him away.
In the aftermath, Dennis ends up in the padded cell of a psychiatric hospital. The reflection still holds sway over him, while the real Dennis remains trapped deep within his subconscious. All that remains is the dream of escaping the carnival ride, a fate he waits to endure again in the quiet margins of sleep.
> "the ride isn't over."
