Kirsty Cotton and her husband, Trevor Gooden, are enjoying a lighthearted drive, filled with laughter and playful banter. As they discuss their day, Trevor is confident they will resolve an issue between them. However, in a moment of distraction, he nearly collides with another vehicle. Instead of a direct impact, their car spirals off a bridge into a deep river below. Trevor miraculously escapes, managing to unbuckle his seatbelt and swims frantically for the surface, calling out for help. Panic sets in as he realizes that Kirsty is nowhere to be found. Desperately, he dives back down to the submerged car, but the doors remain locked with Kirsty trapped inside, unable to free herself from her seatbelt. He is left powerless, watching in anguish as she succumbs to the water.
Awakening in a hospital bed, Trevor suffers from memory loss and excruciating headaches. Authorities inform him that Kirsty is missing, perplexingly noting that her door was open at the time of the accident, contradicting his insistence that it was locked. Plagued by nightmares of a surgeon performing gruesome operations on him, Trevor begins to unravel the disturbing truth about their relationship, including a tape that reveals he had gifted Kirsty the Lament Configuration as an anniversary present.
Complicating matters, Trevor is infatuated with his boss, Gwen, yet his dreams take a sinister turn when he envisions a video recording of two Cenobites brutally murdering her. His romantic entanglements also include Tawny and Sage, leading him to a nightmare where he discovers Tawny lifeless in a chair. In a chilling moment, Pinhead presents him with a note declaring, “All your problems are solved,” only for him to find the body vanished upon waking. When he encounters Tawny again, she seems to have no memory of their time together, having moved on with another man.
As Trevor investigates further, he realizes that Dr. Allison—who has been appearing to him—exists only in his mind when the janitor fails to notice her. The plot thickens as it becomes clear that Trevor is not the innocent man he portrays. Instead, he has conspired with his friend Bret to murder Kirsty for her inheritance tied to Larry and Frank's funds. With Gwen presumed dead and Trevor under suspicion for multiple murders, only Detective Lange believes in his innocence. Trevor’s nightmares reveal his guilt as Bret confronts him over the botched plan to murder Kirsty and make it resemble a suicide, ultimately leading Bret to take his own life in despair.
In a frantic wakefulness, Trevor experiences yet another nightmare where Sage attempts to end his life, only to awaken and discover she has been murdered in a gruesome fashion. Detective Lange arrives, clarifying that the day has taken a dark turn; a body has been discovered in the river. Trevor is led to the morgue, uncovering a shocking revelation that Lange and another detective are, in fact, manifestations created by Pinhead.
Confronted with the grim truth, Trevor sees a corpse covered by a sheet. As he is drawn to unveil it, Pinhead ensnares him with chains, revealing the horrific reality: when Trevor made Kirsty solve the Lament Configuration, intending to sacrifice her, she instead exchanged her own life for five souls. After ruthlessly shooting Gwen, Tawny, Sage, and Bret, she aimed the gun at Trevor, leading to the crash—and revealing that he was the fifth soul, eternally trapped in hell.
Back in reality, following the tragic accident, Kirsty insists Trevor shot himself. The investigation into the supposed killings is marred by the revelation of the gun’s ballistics tying Trevor to the murders. In a twist of fate, all the figures from Trevor's hell materialize in the real world—including Dr. Allison and Detective Lange, while the ghostly surgeon from his dreams is revealed as a coroner.
As the police discuss the harrowing incidents, Detective Lange presents a bag that was retrieved from the car: the Lament Configuration. He informs Kirsty that this item was a valuable anniversary gift from Trevor, suggesting its importance should warrant a personal return rather than evidence. Although she is visibly reluctant to accept it, fearing the implications, she ultimately takes the box, her grip tightening as she walks away, burdened by the weight of her decisions and the haunting remnants of her past.
