This starts with some stupid teenagers deciding to throw a party in the fourth floor of an abandoned hospital. Several years ago a serial killer known as The Mangler died there and it is believed that he haunts the fourth floor. The party is held on the anniversary of his death. Then the story follows a younger kid named Brandon after his encounter with The Mangler. 

This has some scary moments but the characters are so underdeveloped that I didn't really care when some of them died. One character who I thought would be more important ended up dying. The ending was definitely eerie and unsettling and has made me want to read more of this series.