Lily Parker is a sophisticated American magazine editor who is on a business trip in Europe with her outgoing best friend Susan Lawson. Susan convinces her to travel from Venice to Paris by train, instead of by plane. They board the Orient Express, where they hope to find romance. Instead, the atmosphere reminds Lily of a train trip 10 years earlier, when she was a 19-year-old college student traveling through Europe with her friend Stacey. On that trip, she met Alex Woodward, an aristocratic Englishman whom she courted, and then never heard from again. On the present day trip, Lily unexpectedly runs into Alex again on the train, who admits that the rendezvous is no coincidence. Enraged over the past, she refuses to talk to him. Through flashbacks, their past story is slowly revealed. They fell in love on a train to Nice and agreed to travel together. Alex wanted to marry her, but his friend Sandy assured him his father would never approve. While having dinner one evening, Alex was excused by one of his father's friends, and never returned. In the present, Alex convinces Lily to have dinner with him, but past conflicts causes her to leave prematurely. She later returns, deciding to give him another chance. They find out they were both married for five years and then divorced, but only Lily's marriage produced a child. Alex reveals that his father pressured him into another marriage, and that he never regretted anything more than leaving her. The conversation soon escalates into them re-starting a passionate affair, but the next morning Lily makes clear that she has no desire of rekindling with him. They go into different routes, until Alex decides to follow her to Paris. Meanwhile, Lily regrets her decision of sending Alex away. She fears she will never love someone again, and thinks the solution is marrying a man she is meeting in London. One day, however after wondering around Paris, Alex finds Lily in a Parisian restaurant with Susan and Lily's young daughter.