Romantic comedy starring Reese Witherspoon and Vince Vaughn as Kate and Brad, a San Francisco couple whose exotic Christmas holiday plans are scuppered by fog. The pair then face the very scenario they had tried to avoid: the obligatory family Christmas. Owing to the divorces of both their sets of parents, the couple are obliged to attend no less than four festive gatherings - a process that leads them to examine both the past and the future in more detail than either of them finds comfortable.