Arthur isn't sure he is happy about the new baby in the family, but when his sister asks for his help in handling the baby, Arthur feels much better.

With all of his classmates in costumes, Arthur can't tell who's who at the school Halloween party, and he nearly faints when Buster passes around bowls of "eyeballs" and "brains!" But when Arthur's little sister wanders off into the scariest house on the street while trick-or-treating, he's got to find the courage to go in and save her. Will Arthur and D.W. make it out alive?

Arthur finds his role as director of the Thanksgiving play a difficult one, especially since no one will agree to play the turkey.