A group of four friends - Millie, Chloe, George and Amy - go on a camping trip. When one of them goes missing after entering an abandoned asylum called Tunstall Court, they split up to search for her. However, the missing friend was killed by Liv, a former inmate who escaped the asylum 10 years ago after having a breakdown and affair. As the others search alone in the dark building, Liv stalks and kills them one by one. Only George escapes, leaving Liv behind in the abandoned asylum.