Continuing from the previous episode, Hiccup attempts to find evidence that Mildew caused the damage to the village, hoping to exonerate the banished dragons. Meanwhile, Alvin the Treacherous of the Outcast Tribe launches a raid on the Isle of Berk in order to find and capture the "Dragon Conqueror".

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.