Elsa plans to give Anna a surprise birthday party with the help of Kristoff, Sven, and Olaf; but while Anna is led on a party treasure hunt by a string that winds through the kingdom, Elsa has caught a cold, and unknowingly produces a group of “Snowgies” with each sneeze, who begin to dismantle the birthday party’s decorations while Kristoff tries to stop them. While Elsa takes Anna on the hunt, Kristoff, Sven, and Olaf try to control the snowmen and fix the decorations in time for Anna and Elsa’s return. Meanwhile, Elsa’s condition rapidly worsens and she becomes delirious with fever. After Elsa nearly falls off a clock tower, Anna convinces her to rest. They walk back to the castle where Elsa apologizes to Anna for “ruining” another birthday, but Anna reassures her that she didn’t ruin anything. As Anna goes to lead Elsa to bed, the doors to the castle open to reveal Kristoff, Olaf, Sven, and a mountain of tiny snowmen, who surprise Anna. Elsa sneezes again and finally sees more tiny snowmen that she produced. Despite Anna’s protests, Elsa concludes the party by blowing into an alphorn. However, she sneezes into the horn, forming a giant snowball that inadvertently hits Hans overseas (and into a cart of manure, as he was cleaning out the stables as punishment for his attempt on Elsa’s life). Elsa rests in bed under Anna’s care while she points out that taking care of her beloved big sister is the best birthday present ever.
Olaf, Kristoff, and Sven escort the small snowmen to Elsa’s ice palace, where they stay with her snow-giant doorkeeper Marshmallow.