The special opens with Lucy taunting Charlie Brown, holding a football for him to kick off the fall football season. Wishy-washy Charlie Brown is talked into it (like always), and once again Lucy pulls the ball away, sending Charlie Brown sprawling and landing flat on his back.
Charlie Brown and Sally are preparing to go to their grandmother's place for Thanksgiving dinner when Charlie Brown gets a phone call from Peppermint Patty who invites herself over to Charlie Brown's house for the holiday dinner. Two quick subsequent phone calls add Marcie and Franklin to the guest list, and since Charlie Brown can't get a word in edgewise with Patty, he quickly finds himself in a quandary with no easy solution -- at least not until Linus shows up.
Linus suggests to Charlie Brown that he could have two dinners: the first one for Patty and her friends, and then the second one at his grandmother's home, forcing Charlie Brown to admit that all he knows how to make is "cold cereal and maybe toast." Regardless, Linus recruits Snoopy and Woodstock to set up a ping-pong table and chairs in the backyard (setting the table has its own problems as Snoopy goes toe-to-toe with an uncooperative folding chaise lounge). Snoopy and Woodstock set the table, then go to help Charlie Brown and Linus with the food. When the food is readied, Snoopy and a defiant Woodstock go to Snoopy's doghouse and dress in pilgrim clothing, which catches Charlie Brown somewhat off-guard.
The guests arrive, and they all make their way to the backyard for the "feast". Linus leads the group in prayer, and Snoopy serves up the food:
Each person gets:
* Two slices of buttered toast (though Peppermint Patty mentions just one)
* Some pretzel sticks,
* A handful of popcorn, and
* A few jelly beans.
At first Patty is shocked, but her shock quickly turns to outrage, and she angrily berates Charlie Brown for the "meal". Embarrassed and dejected, Charlie Brown timidly leaves the table and goes back into the house. Patty's ranting continues until Marcie gently reminds her that Charlie Brown didn't invite her to dinner; she invited herself -- along with Marcie and Franklin. Realizing Marcie is right, Patty comes to her senses and begs Marcie to go and apologize to Charlie Brown on her behalf. Marcie reluctantly does so, but Patty soon follows her and apologizes to Charlie Brown herself.
In the midst of the quasi-feast, Charlie Brown loses track of the time -- he and Sally are supposed to be at their grandmother's home for dinner in half an hour. So he calls his grandmother to tell her that they're going to be a little late and to explain the situation -- that he has friends over and none of them have eaten yet. But his grandmother (voiced only by "tromboning", the specials' trademark muted trombone) suggests that he bring all his friends with him for Thanksgiving dinner; the idea is greeted with cheers from everyone.
After Charlie Brown and the gang (sans Lucy) leave, Snoopy and Woodstock go to the doghouse and cook up their own traditional Thanksgiving meal complete with all the trimmings (they pull apart the wishbone, with Woodstock getting the bigger piece). Over the end credits the two friends each devour dessert -- a large piece of pumpkin pie, and then sit back patting their respective stomachs.