When a group of filmmakers investigate an abandoned asylum famed for its mysterious disappearances, they soon discover the truth is far more terrifying than they could have ever imagined. Led by director Richard Macintosh and researcher Mary Price, the filmmakers plan to spend the weekend inside the walls of Cain Hill Psychiatric Hospital to produce a documentary about the goings on. Famous for the many unexplained disappearances and tales of a murderer called Chester Lockhart, the team aim to capture the truth behind the famous Cain Hill Asylum. Once inside and set up they soon discover that the stories about Cain Hill aren't just local tales, and they discover that they are not alone. What was planned as a low budget documentary shoot soon becomes a game of cat and mouse, with a psychopath determined to kill the intruders who have entered his home.