In London, Iris (Kate Winslet) is a newspaper wedding columnist recovering from unrequited love. In Los Angeles, movie trailer editor Amanda (Cameron Diaz) is keen to forget her cheating ex-boyfriend.

Both are desperate for an escape – and through a house exchange website they find one, with Iris jetting off to Amanda's California mansion while Amanda takes up Iris's Surrey cottage for the Christmas holidays. But when they both find someone special in their new-found locales (Jude Law, Jack Black), they realise they might have a good reason to stay.