Two years after the events in Cheaper by the Dozen (2003), football coach Tom and author Kate Baker plan a vacation for the whole family. However, instead of having a peaceful summer vacation at a picturesque lakeside resort, the Bakers embark on an outrageous competition with Tom's long-time rival, obnoxious Jimmy, and his overzealous clan. Now, let the games begin. But who will win? Will the two fathers ever bury the hatchet and become friends?