An ad exec and family man, Charles Schine (Clive Owen), meets business woman, Lucinda (Jennifer Aniston), on the commuter train to Chicago. Flirtation quickly escalates, but their fling turns dangerous when a violent criminal, LaRoche (Vincent Cassel), blackmails them, promising to reveal their indiscretion and threatening their families if they not pay him. With their lives thrown terrifyingly off-course, they must figure out how to turn the tables on LaRoche and save their families.