Quick recap
Madguts the Murderous invites the Hooligans and the Bog-Burglars to a swimming race between tribes. The last one back wins and gets a wish from the three chiefs. Mid-race, Hiccup, Camicazi and Fishlegs are kidnapped and taken to a ship, while Stoick and Bertha end up in a cell. On board, Hiccup meets slaves, the Northern Wanderers, who offer a deal: they spare his life if he helps them escape. A storm, a sea monster and a mark that won't come off his skin are waiting.
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