A traditional painted portrait of Berk's Chief and his son exaggerates Hiccup's muscularity and size and causes him to worry that he is not Stoick's ideal son. Hiccup is determined to prove himself by accomplishing the treasure-hunting quest of Hamish II, a quest that even Stoick and Gobber had not been able to complete.

The teens of Berk find a mysterious girl named Heather on Thor's Beach. While Hiccup and the other teens openly welcome the newcomer, Astrid's jealousy turns to suspicion when she notices Heather is taking an unusual interest in the Book of Dragons. Unfortunately it is found she was working with the Outcasts and, despite the Dragon Riders' effort, she manages to give the ancient Book of Dragons to Alvin.