18 long years have passed since the dragons finally disappeared and life on Newberk couldn't be better. Everyday life is peaceful and blooms with life. Nevertheless, no one has forgotten the old stories. The stories of Hiccup and his dragon Toothless, who have saved Berk from the dangers out there time and time again. Despite the loss of the dragons, their friends, no one thinks about bringing these beautiful creatures home. So why is it that the giant reptiles suddenly dominate the skies and sea again? How can it be that Mira sees a dragon? What happened in the Secret World that made her return or even flee?