David has traveled to New York with his wife to visit his new publisher. On his way back to Penn Station, he bumps into a stranger who covertly follows him, and then, just before they board the train home, passes him by close enough to whisper: "Remember me." The stranger follows David and his wife back to where they live, and it isn't long before he realizes that this man wants something from him...something very personal, that he may have no choice but to surrender.

Bill Moore has a lucrative job selling condos in the Florida Keys, a successful wife, a good marriage, a beautiful house. Then one morning Bill arrives at work to find a card waiting for him, with no indication who it's from or why it was sent. Its message is just one word: modified. From that moment on, Bill's life begins to change.