On Christmas Eve, Mr. Grouper tells the Bubble Guppies the story of how Gil, Molly and Bubble Puppy discover Santa's lost list in the snow. To return the list safely to the North Pole, they have to keep it out of the hands of the Christmas-hating Humbug.

Mail Carrier Molly tries to deliver a Friendship Day card for someone named Alison in a place called Wonderland; the card-stealing Queen of Hearts bans Friendship Day across the land.