"It's the Great Pumpkin, Charlie Brown" is a Halloween special based on Charles M. Schulz's comic strip "Peanuts," in which Linus tries to prove that the Great Pumpkin truly exists. After writing the Great Pumpkin a letter, Linus skips trick-or-treating and waits for the Great Pumpkin in a pumpkin patch.
In "It's the Great Pumpkin, Charlie Brown," Linus' friends laugh at him when he claims that there is a Great Pumpkin. When writing the Great Pumpkin a letter, Linus informs the Great Pumpkin that more people believe in Santa Clause than they do him, but it's only because Santa receives more press.
On Halloween night, everyone gets in their costumes and prepares to go trick-or-treating, except for Linus, who sits in a pumpkin patch waiting to catch a glimpse of the Great Pumpkin. The group stops by the patch to make fun of Linus for missing out on the Halloween fun. Linus convinces Sally to stay behind with him. During the night, Snoopy appears as a shadow over the pumpkins causing Linus to faint, thinking he has just seen the Great Pumpkin. Upon realizing it is Snoopy, Sally becomes outraged at Linus for wasting her time and she storms off.
At 4 a.m., Lucy discovers Linus still hasn't come home. She finds him shivering in his blanket in the pumpkin patch and brings him home. The next day, a defiant Linus continues to argue that the Great Pumpkin will appear next year.