The friends become trapped in the hospital and they are unable to find a way out. As they walk all around the hospital, different members of the group begin to disappear one by one. It turns out that a killer is loose in the mental ward and he is picking off the explorers one by one. He chases one girl down a narrow hallway and corners her in a small room. The girl manages to escape by lying one a shelf out of the killer's view.
There are even conflicts between the various members of the group. One guy is injured by the killer and the group of girls with him run away in fear rather than help him. Later, they return to try and give aid but the injured guy is furious. As they are assisting him, he sees the killer return and fails to warn them. The group also thinks that one of the girls is working with the killer. They decide to tie her up so she cannot hurt them. Unfortunately for her, the group is wrong and the killer ends up finishing her off.