When a series of lightning storms hit Berk, Vikings claim Thor is angry for allowing Toothless, a dangerous Night Fury, to live among them, so it's up to Hiccup to prove Toothless's innocence before he is banned from Berk forever.
Describes the different dragons Hiccup has met along his journeys, from the fire-breathing Monstrous Nightmare and the rock-eating Gronckle to the two-headed Hideous Zippleback and Hiccup's own Night Fury, Toothless.
When Hiccup is kidnapped by a mysterious dragon rider, he discovers the fate of his mother, Valka, and how the dragons of Berk needed to be rescued from the evil plot of Drago, the terrible dragon thief.