A holiday gathering threatens to go off the rails when Ned Fleming realizes that his daughter's Silicon Valley millionaire boyfriend is about to pop the question.
Wilbur the pig is scared of the end of the season, because he knows that come that time, he will end up on the dinner table. He hatches a plan with Charlotte, a spider that lives in his pen, to ensure that this will never happen.
When the Johnsons' present for Grover is stolen, Calvin and Dave team up to recover the gift in time for the holiday; a nostalgic Tina tries to get into the Christmas spirit by reviving traditions from when Malcolm and Marty were kids.
