Hiccup Horrendous Haddock III was an awesome sword-fighter, a dragon-whisperer and the greatest Viking Hero who ever lived. But it wasn't always like that. Hiccup's memoirs look back to when Hiccup was just an ordinary boy, and finding it very hard to be a Hero. Can Hiccup find Grimbeard the Ghastly's treasure before Alvin the Treacherous gets his sneaky hands on it? And if Hiccup opens a box that says 'Do Not Open', will he live to tell the tale?