WARNING: The premise of this film contains unmarked spoilers for the series thus far.
Since the fall of the Red Death, the Vikings of Berk have made peace with the dragons forced to do its bidding, and they live together in harmony. In just five years, the dragons have radically altered the culture of the village. Every Viking has now bonded with a dragon, and they even stage competitions to see who can capture more sheep. During one such competition, Hiccup, the son of the village chieftain Stoick the Vast, secretly leaves with his own dragon, Toothless, to explore uncharted lands.