One Bad Thing poses the question: Can an otherwise good man commit an act of evil and go back to living his life unscathed?
The story opens in the Virgin Islands. Rob McKenna is a good man who has lost much: His beloved daughter was killed the year before. McKenna's wife leaves him, forcing him to take on a crewmember, Tom Cain, to help sail the boat back to Boston. But Cain brings trouble on board and forces McKenna to make a desperate choice. "Do this one thing," Cain says. "Do this and you'll have a life." All McKenna has to do is lie. And soon... kill.