It's Thanksgiving, and Charlie Brown and Sally are invited to their grandmother's house for dinner. Unfortunately, Peppermint Patty invites herself to their house, along with Marcie and their friends. Snoopy is in charge of cooking, but Peppermint Patty is horrified at what he cooked and thought Charlie did so: toast, pretzel sticks, popcorn, and other things. Marcie sees how she feels, and comes to Charlie's rescue. He thinks he can invite everyone else to his grandmother's house, and the day is saved!