Distraught after his breakup with ex-girlfriend, Brenda, Wes finds himself at a desolate roadside rest stop. That night, in a haze of heartbreak, he succumbs to blackout drinking, leading to the burning of his possessions—his pants and a box filled with cherished photographs. The next morning, feeling worse for wear, he stumbles into an empty restroom only to be overwhelmed by nausea.
While in a stall, he hears a strange voice belonging to a mysterious being named Ghatanothoa, who claims to be a demigod brought into existence by an accidental creator, his celestial father. As their conversation develops, Wes quickly realizes that the restroom door is firmly sealed, cutting him off from the outside world. Ghatanothoa warns Wes against looking at it, explaining that seeing its true form would lead to his destruction. Ignoring the warning, Wes tries to catch a glimpse through the glory hole, an act that gets him punished with haunting visions of Brenda.
In a desperate attempt to escape, Wes tries to crawl through the air vent but, instead, finds himself back in the restroom. Ghatanothoa clarifies its backstory, revealing it was designed to be a tool for destruction, yet it has chosen to hide from its father to protect humanity, a race it has developed feelings for. However, in order to transcend into the ethereal plane permanently, Ghatanothoa needs mortal satisfaction—a process that, unfortunately for Wes, occurs through the notorious glory hole.
Both terrified and trapped, Wes challenges Ghatanothoa’s pleading for assistance, disclosing his own traumatic past involving an abusive father and his singular devotion to Brenda. Suddenly, a maintenance worker enters and, against Ghatanothoa's warnings, Wes screams for help. The poor man becomes a victim to Ghatanothoa's wrath, explosively turned into a gory spectacle to keep the secret buried.
Desperate and frustrated, Wes resorts to extreme measures, attempting to force open the restroom door with a dismembered leg but eventually loses hope. In a climactic moment, he inserts himself into the glory hole, only for Ghatanothoa to clarify that "satisfaction" refers to the offering of a piece of his liver. The demigod hands Wes a shard of broken glass, triggering an intense retreat from his original plan.
As the pressure mounts, Wes calls out for Ghatanothoa's father, inadvertently unraveling the barriers between dimensions as the rest stop begins to crumble. In a moment of desperation and clarity, Ghatanothoa erases Wes's memories of Brenda to show him the catastrophic consequences of universal annihilation. Reluctantly, Wes agrees to help, desperate to see Brenda once more.
With renewed memories, the gravity of the situation grows heavier as Ghatanothoa's father breaks through the fabric of reality. In a final act of sacrifice, Wes inflicts pain on himself, cutting open his abdomen to deliver a piece of his liver to Ghatanothoa, allowing it to escape its father's grasp. As Wes collapses, he confronts the memories of his past—a revelation that he was a serial killer, having murdered Brenda when she stumbled upon the photographs of his victims.
As Ghatanothoa ascends into the ether, Wes weakly questions if his actions make him a hero. With a somber farewell, Ghatanothoa insists they are not heroes, but mere destroyers destined to fade away. In the end, Wes takes his last breath outside the restroom, clutching a teddy bear given to him by Brenda, engulfed in the melancholy of his choices.
