The Viking town of Berk, now enjoying its new alliance with the dragons, is preparing for its annual winter holiday of Snoggletog. However, that spirit is threatened when all the dragons, except Toothless who needs Hiccup to help him, suddenly fly away for some reason. While Astrid ineffectually tries to salvage the occasion, Hiccup decides to build Toothless a new prosthetic to allow him to fly independently, only to have the dragon take off as well. However, as the holiday approaches, Hiccup finds himself swept up to learn the dragons' secret the hard way and to find a solution to bring them home early.

The Winter Feast is Po's favorite holiday. Every year he and his father hang decorations, cook together, and serve noodle soup to the villagers. But this year Shifu informs Po that as Dragon Warrior, it is his duty to host the formal Winter Feast at the Jade Palace. Po is caught between his obligations as the Dragon Warrior and his family traditions: between Shifu and Mr. Ping.