Boo (2005)

The friends Emmett, Freddy, Marie, Kevin and his reluctant girlfriend Jessie decide to spend the Halloween night in an abandoned hospital. Meanwhile, the younger Allan meets the old friend of his father Arlo Ray Baines and asks him to help to find his vanished sister Meg in the same spot. The two groups meet each other in the mental institution section on the haunted third floor and they find that they are trapped in the place.