David Dunn is a listless security guard returning by train to his home in Philadelphia. Though he loves his young son Joseph, he hasn't felt good about himself in years and his relationship with his equally depressed wife, Audrey, is just about over. Into this uneventful life comes a terrible train wreck. More than 100 people die--everyone on that Philadelphia-bound train, in fact, with a single exception. David Dunn not only comes out alive, he emerges without a scratch on him. The notoriety of his survival leads directly to something left on his car windshield, an unsigned note asking if he's ever been sick. Intrigued, Dunn not only investigates the history of his own health but also tracks down the man who left the message, comic-art dealer Elijah Price. Though Price suffers from a strange and rare bone disease that makes him fragile to the touch, it is the explanation as to why Dunn survivied the wreck that is nothing short of extraordinary.