After suffering an explosion at the hands of a terrorist bomber, detective Ben Walls awakens in a hospital and is forced to remain inside the building at the behest of his Captain. As Ben navigates the hospital's alarmingly empty hallways, he soon finds himself hunted by a self-proclaimed avenging angel and haunted by apparitions whose deadly motives remain a mystery. Now Ben must find a way to both stop the supernatural forces that want him dead and catch the bomber before he strikes again.