An atomic explosion awakens Gammera--a giant, fire-breathing turtle monster--from his millions of years of hibernation. Enraged at being roused from such a sound sleep, he takes it out on Tokyo.

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.

Dot, an Australian girl, seeks the magical green root that will give her the ability to talk to animals. She eats a red root by mistake, and is shrunk to the size of an ant. With the help of her friends Keeto the mosquito and Butterwalk the caterpillar, she searches for the green root that will restore her size. But she must find it before sundown, or she will shrink even smaller.

Fantasy adventures of a little redheaded girl and her animal friends in Australia. Live background and animated characters.

Dot promises a mother kangaroo that she will find her lost joey. An orphaned rabbit overhears this promise and pretends to be a kangaroo because he wants a mom. Dot and the rabbit travel through the Australian outback and learn a lot about different kinds of animals.