A decade after the death of millionaire Cyrus Norman, his will is finally set to be read at his eerie, isolated mansion located in the Louisiana bayou. The potential heirs gather, including Joyce Norman, a distant relative, who brings along her friend Wally. Adding to the tension, they are informed by the caretaker, Miss Lu, that the estate is believed to be haunted by Cyrus's dissatisfied spirit. As the night progresses, the assembled guests are startled by a mysterious figure known as "The Cat," who has been terrorizing the area with a series of murders. The group learns that whoever inherits the fortune must be deemed sane by midnight or the next heir will inherit everything.

During the unfolding events, eerie occurrences and sudden disappearances heighten the sense of paranoia among the guests. Joyce is declared the main heir but becomes increasingly anxious as unsettling incidents occur around her. Meanwhile, Wally attempts to use his wit and humor to navigate through the escalating danger, providing both comic relief and unexpected bravery. With the house shrouded in darkness and suspicions running high, each person must confront their deepest fears. Amidst a growing sense of dread and the elusive threat of 'The Cat,' secrets are unveiled and alliances are tested, leading to a tense and gripping scenario that promises grave consequences for all involved.