In the 1950s, a young American woman living in London, Cary Porter (played by Ringwald), starts working at a large multinational firm where she meets accountant Ian Bertram (played by Lindsay). He falls head over heels in love with her and soon proposes. The head of the company, Herbert Dreuther (played by Gielgud), offers them a wedding and to pay for a honeymoon in Monte Carlo, as well as the use of his yacht.

Unfortunately, the well-meaning Herbert soon forgets all about the couple and his promise to send his yacht. When it does not arrive, Ian decides he has a sound way to win at roulette in order to pay their large hotel bill. As he becomes involved at the gambling tables, he leaves Cary to herself, and although his plan works and he wins big, enough to pay their bill, get them home, and have plenty money left over, their marriage is in big trouble.