Guy Carrell, a wealthy Victorian-era Englishman, is obsessed with the fear of being buried alive. His phobia stems from the belief that his cataleptic father suffered such a fate. Determined to avoid a similar end, Guy constructs an elaborate tomb designed to prevent premature burial, equipped with breathing tubes and escape mechanisms. Despite his fiancée Emily's reassurances, his dread only grows more consuming, straining their relationship and isolating him from friends and family. Guy's relentless fear drives him to become increasingly paranoid, leading him to test and retest his tomb's many safety features.

As Guy's mental state deteriorates, Emily and his sister, Kate, become increasingly concerned about his well-being. Guy believes that those closest to him might have sinister motives, intensifying his paranoia. His fears come to a head when a series of unsettling events and misunderstandings amplify his terror of premature burial. The tension mounts as he wrestles with his sanity and the trustworthiness of those around him, leaving everyone to question whether Guy's fears are grounded in reality or merely the product of his tormented mind.