The life of Brad (Vince Vaughn Vince Vaughn) and his girlfriend Kate (Reese Witherspoon Reese Witherspoon) is like an ordinary couple, the only difference is that they are unmarried and have no children, but they have one more headache than the average couple, that is, their parents are divorced and live separately, so the couple visit four parents every Christmas. In the past two years, Brad and Kate were lucky enough to avoid complicated family gatherings under the pretext of official business, and both flew to the tropics to celebrate the New year. However, this year is not so smooth, flights are all cancelled due to heavy fog, the couple can not go on holiday, but also inadvertently was photographed and put on the TV news. The escape plan fell through, the two had to run to their parents' Christmas party in one day, not only walking and running all the way, but also four families did not make them worry, and farce appeared one after another.