Hiccup Horrendous Haddock III, the reluctant Viking hero, tries to make the most of his somewhat limited time to discover America, return to Berk, save his father, fight Polarserpents, and win a swimming race.
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.
Someone has stolen the fire stone, so eggs of exterminator dragons are hatching. Hiccup must find and return the fire stone to the volcano to save the Tribes from being wiped out.
Recounts the further escapades of Hiccup Horrendous Haddock the Third as he continues his Viking training during which he escapes from a boatload of Roman soldiers and searches for his kidnapped dragon.
Hiccup Horrendous Haddock III tries to save his dragon, Toothless, from being banished, but first he must steal a carefully stored Viking book from the Meathead Public Library, where he is sure to encounter the Hairy Scary Librarian and his army of warriors and dragons.
Hiccup and Toothless discover a secret ice cave that is home to hundreds of new wild dragons and the mysterious Dragon Rider, and the two friends find themselves at the center of a battle to protect the peace.