Berk lands have become a prosperous land, human beings and dragons live happily. Hiccup was suddenly blamed on sabotage by a group of dragon hunters. However, Hiccup is known a dangerous person - Drago blood face is looking for the area of ​​Berk destroy all. Then, suddenly ,cccc found Valka - the biological mother supposedly dead 20 years ago. Valka leads Hiccup to the sacred land - inhabited by most dragons and a giant mother dragon. Valka reveals everything she has learned for 20 years, expresses her apology and wishes for peace everywhere between dragons and humans because she also has the same ability as Hiccup, the ability to tame dragons.

Stoick reunited with Valka. Both of them regain their old love, thinking that they could live happily together, when Drago bloody face ordered the mother dragon to control the entire dragon species. And Toothless, with control, shot Stoick to kill Hiccup.

Hiccup gradually regained Toothless by his precious friendship, and with the immense power of the Night Fury, Toothless defeated the giant mother dragon, becoming the Dragon Head. Hiccup's victory also helped him to become the Viking head of Berk, partly because his father lost Stoick.