Jerry Hickfang's existence is a chaotic intertwining of reality and delusion, revealing the complex nature of his schizophrenia. By day, he endures a monotonous routine working at a plumbing fixtures factory, and at night, he's isolated above a bowling alley, with the sounds of laughter and clattering pins echoing in the void of his loneliness.
As Jerry grapples with his fragmented mind, he tries to manage the conflicting narratives he shares with his court-appointed therapist, Dr. Warren. In his troubled mind, he believes he converses with his lovable dog, Bosco, and his sardonic cat, Mr. Whiskers, who lead him through bizarre dialogues.
Jerry’s attempt at a social life takes a turn for the worse when a dinner date with his coworker Fiona falls apart as she opts for karaoke with friends Lisa and Alison. However, when he drives Fiona home after her car breaks down, the encounter spirals after a deer crashes through his windshield, which seems to plead for mercy with its eyes.
In a dark twist of fate caused by his hallucinations, Jerry interprets the deer's gaze as a cry for him to end its suffering—an action which sets off a tragic chain of events. Fiona's sudden flight into the woods from the distressing confrontation leads Jerry down the path of violence, resulting in a horrifying accident where he wounds her, then, in a panic, proceeds to inflict fatal harm, overwhelmed with regret and tears.
Back at his increasingly chaotic home, Bosco beseeches Jerry to contact the authorities, while Mr. Whiskers instills feelings of shame that prevent him from doing so. Consequently, Jerry takes a menacing route—dismembering Fiona's body and stowing her remains in Tupperware, haunted by the chilling demands of her decaying head that urges him to resume his medication.
As reality continues to blur, Jerry confronts flashbacks of his abusive father, which have marred his psyche. Waking to a grotesque landscape of garbage, animal waste, and blood, he makes the fateful decision to discard his medication, thus reopening the floodgates of his troubling hallucinations. Fiona’s head now becomes a grotesque muse, insisting that he finds “a friend” for her, and with Lisa as his potential next victim, he lures her to his childhood home—haunted by memories of his mother’s tragic demise.
Just as Jerry prepares for new violence inspired by his mother's death, the unexpected presence of Lisa pulls him from the edge. She offers comfort and a kiss, anchoring him back to reality. However, the gruesome reality of Fiona’s remains causes a confrontation with the past, forcing him to face the grotesque drive propelling his heinous actions—realizing that the voices urging him on are mere fabrications of his deteriorating mind.
When Lisa unexpectedly shows up at his home, the horrifying condition of his apartment is revealed—fiona’s head among other remnants of his crimes. In a gruesome turn, Jerry succumbs to his delusions yet again, leading to another horrific act where he dismembers Lisa and preserves her head with Fiona’s in his refrigerator.
Amidst the shock of Lisa's disappearance, Jerry's coworkers scramble to piece together the truth. As they uncover the dark history of his past—including his mother’s death—Alison ventures into his apartment but meets her end at Jerry’s hands, who is spiraling further into madness as he builds a dreadful collection of severed heads.
Faced with the cacophony of voices in his head, Jerry feels compelled to confess to Dr. Warren regarding his gruesome acts, prompting him to kidnap her in a frenzied bid for guidance. As the authorities close in on his crumbling reality, he spirals deeper into insanity, taking Dr. Warren to the bowling alley—where chaos ensues leading to a catastrophic gas leak explosion.
In the aftermath of fiery destruction, Jerry finds himself caught between the insistent urging of Mr. Whiskers to continue his spree and Bosco’s counsel to surrender. Ultimately, he succumbs to the smoke and flames, existing in a surreal void where he reunites with his deceased companions. Here, a strange reconciliation occurs as Mr. Whiskers and Bosco confront their differences, culminating in an unexpected visitation from Jesus. This leads to an eccentric celebration of life, death, and redemption through song and dance, leaving Jerry to offer heartfelt apologies to his victims—Fiona, Lisa, and Alison.
