Dennis, a college-age young man and an adoptee, wakes up in a small private hospital in San Francisco after a minor car accident to discover that one of his organs is missing. He's an involuntary transplant donor. He flees to a municipal hospital, only to learn that this is the second organ to be harvested from him.
He runs for his life. Clearly someone, somewhere, is a close match for him, needs his organs, and knows his every move. The next time, he might lose his heart or lungs. He won't wake up after that.
Dennis heads home to Boston to confront his adoptive father, who seems to have forged his name to a donor card. And so the hunt is on: Dennis must find his harvester before the harvester finds him again.