Linus evangelizes on behalf of the Great Pumpkin, a supernatural being he believes in. He is convinced that the Great Pumpkin will appear on Halloween Night in the pumpkin patch, and plans an all-night vigil. He tries to get others to join him. No one is convinced. Charlie Brown's little sister Sally finally gets involved, but she is completely uninterested in the metaphysics of the Great Pumpkin. Rather, she wants to spend time alone with Linus, whom she likes. The attraction is not reciprocal, but Linus gladly takes her on as another disciple of the Great Pumpkin.
At one point, Schulz has Linus write a letter to the Great Pumpkin saying:"Everyone tells me you are a fake, but I believe in you. P.S., If you really are fake, don't tell me. I don't want to know."
Night comes; the Great Pumpkin doesn't show up; Sally gets annoyed and storms off; Linus stays loyal and remains at his post. The next thing we know it's 4 AM, and -- shivering and having fallen asleep still at his vigil post -- Linus is dragged inside and put to bed.
On the morning of November 1st, the show ends with this exchange:
Charlie Brown: [Dejectedly] Well, another Halloween has come and gone.
Linus: [More Dejectedly] Yes, Charlie Brown.
Charlie Brown: I don't understand it. I went trick-or-treating and all I got was a bag full of rocks. I suppose you spent all night in the pumpkin patch.
Charlie Brown: And the Great Pumpkin never showed up?
Charlie Brown: Well, don't take it too hard, Linus. I've done many stupid things in my life, too.
Linus: [Shocked] [Turns angry] "Stupid"? What do you mean, "stupid"? [Flails arms in frustrated anger] Just wait till next year, Charlie Brown! You'll see. Next year at this same time, I'll find a pumpkin patch that's real sincere. I'll sit in that pumpkin patch until the Great Pumpkin appears. [Finger in the air, as pontificating] He'll rise out of that pumpkin patch and fly through the air with bags of toys. The Great Pumpkin will appear! I'll be waiting for him. I'll be sitting there in that pumpkin patch and I'll see the Great Pumpkin. Wait and see, Charlie Brown! I'll see the Great Pumpkin! [End of Show]
At the same time, Linus is a sympathetic character throughout (despite his show-ending diatribe). Watching the show, we want the Great Pumpkin to be real. Linus as a tragic hero. When Snoopy pops up in the shadows, for a split second, we, along with Linus and Sally looking on, want to believe it is the Great Pumpkin itself.
And alas, was Linus' Halloween (an all-night vigil) really any worse spent than Charlie Brown's own, who tried to have his fun but ended up with a bag full of rocks?