Chronicles the adventures and misadventures of Hiccup Horrendous Haddock the Third as he tries to pass the important initiation test of his Viking clan, the Tribe of the Hairy Hooligans, by catching and training a dragon.

Follows the further adventures and misadventures of Hiccup Horrendous Haddock the Third as his Viking training continues and his father leads a stranger and the Hairy Hooligans to the Isle of Skullions in search of a pirate's treasure.