During the holiday season Stanley, Lester, Marci and Mimi find a lost puppy in the park. To keep it out of the cold, Stanley's Mom agrees to take him in until they find the owner. The puppy (named Little Dude) chooses Harry as his mother, but Harry and Stanley don't know how to take care of a puppy, so they do research. But when Little Dude jumps into the Great Big Book of Everything, Stanley and friends must jump into the book to get him back. Once out of the book, Little Dude's real owner shows up.