Delirium is a horror movie that follows the story of Tom, a man who has just been released from a mental institute after being treated for a nervous breakdown. He arrives home to find out that his parents have passed away and he has inherited their mansion. With nowhere else to go, Tom moves into the mansion.
As he spends time in the house, Tom begins to experience a series of disturbing events that make him question his sanity. He hears strange noises, sees weird things, and feels an eerie presence around him. Even his old friends who visit him in the mansion start to notice something strange about the place.
Convinced that the mansion is haunted, Tom hires a psychic to investigate. The psychic confirms that the place is haunted by the ghosts of Tom's ancestors who were killed in a massacre many years ago. Tom starts to dig into his family history and discovers a dark secret that could explain why the ghosts are haunting him.
As the movie progresses, Tom becomes more paranoid and terrified of the ghostly presence in the house and he works to uncover the truth about his past and the mansion. The tension builds to a climactic finale where Tom must confront the malevolent spirits and put an end to the haunting once and for all.