When upscale, happily unmarried San Francisco couple Kate and Brad find themselves grounded by fog on Christmas morning, their exotic vacation plans morph into the family-centric holiday they had, until now, gleefully avoided. Out of obligation, they trudge to not one, but four relative-choked festivities, increasingly mortified to find childhood fears raised, adolescent wounds reopened... and their very future together uncertain. Brad counts the hours to when he can get away from their parents,...