The episode starts off with a comic book about the KND. The beginning of the comic book shows Santa's workshop with all the elves working hard over toys that Santa will deliver. A knock on the door is heard, and when answered, the elf is hit by a sleeping-gas dart. The KND appear, with gas masks, and even with the nice, cheerful greetings by the elves, they are shot by darts and have a happy nap. The KND soon reach Santa's workplace.
The next scene shows the KND returning to the treehouse and one present, with Numbuh 3 excited about the gift exchange, which, everyone seems to have forgotten. The KND are prepared to land at the treehouse, but it's gone! Numbuh 1 is mad, but is attacked by the Elfa Strike, which consists of Wintergreen, Coniferous, Snow Angel, and Nutcracker. They're looking for Santa's reindeer, and soon attack the KND while Numbuh 3 holds what seems to be Numbuh 4's present. The narrator gives a summary of each Elfa Strike member as they appear. The fight continues to go on, and the fight quickly ends when Wintergreen uses their ultimate weapon: The Twelve Days of Christmas. Wintergreen soon takes the present from Numbuh 3 and opens it, expecting reindeer, but it turns out to be a Reindeer Monkey, which the KND bought at the mall. Everyone looks confused as the scene goes back to the North Pole
The KND beak into Santa's room and take off their masks to reveal that they're the Delightful Children from Down the Lane. The Delightful Children push Santa off the ledge, (but before they do, he tells them that they shouldn't mess with the power in the sleigh), and use his sleigh to make every child around the world have coal so they can have everything.
The KND and the Elfa Strike return to the North Pole and try to get to Santa's room, but is stopped by a substitute teacher hired by the Delightful Children. She sends in 4 members similar to the Elfa Strike and have a confrontation. Wintergreen tells the KND to break into Santa's room using the chimney. They break in, only to find that the Delightful Children have turned green and are asking for help.
Outside Santa's room, the bad guys are tied up, and Christmas is saved, but Numbuh 3 is missing. She goes back to Santa's sleigh, and tired of nobody getting her a gift, she uses the Delightful Children's plan, but this time, for herself and only her.
Santa tells Numbuh 4 that he is the only one that can stop Numbuh 3's wrath and pushes him in. Numbuh 3 is green, and angry, and things don't get better until Numbuh 4 gets her a gift, which is fries from a fast food restaurant. She calms down and a hug is exchanged. Numbuh 1 and Wintergreen shake hands and asks what happened to the treehouse. Wintergreen says he put it to a good use, and we see it outside a ice skating area.