Until now, Brad(Vince Vaughn) and Kate(Reese Witherspoon) had always managed to avoid spending Christmas with their family by escaping to exotic lands to enjoy heavenly vacations. But this year, they failed. When they arrive at the airport, all the flights have been canceled. Even worse, a television news crew interviews them, revealing to their family where they are. This time, there's no way out and no excuses. Brad's father is waiting for them at his house. So is Kate's mother. And Brad's mother and Kate's father. Four family Christmases, the same day! Brad and Kate expect the worse... and they won't be disappointed. They will be spared of nothing. In between humiliations, the secrets each one of them had carefully kept from the other, the hard feelings and impossible situations, the couple will live through a day that might be the last their relationship can stand.