A massive conflict erupts on Outcast Island involving the Riders, Alvin's forces, and the Berserkers. The Screaming Death eventually reunites with its mother and leaves the archipelago in peace. Key Outcomes & Trivia
Snotlout, who was suspended in the previous episode, proves his worth during the battle, leading Hiccup to lift his suspension.
Hiccup decides to trust Alvin the Treacherous , who has returned seeking to make amends. Together, they infiltrate Outcast Island via a secret underwater tunnel system.
With Stoick gone, Hiccup is appointed Acting Chief for the first time. He struggles to maintain order as the villagers of Berk riot and call for war.
Both Alvin the Treacherous and Mildew receive forms of redemption. Alvin and Stoick finally bury the hatchet and end their years of hatred.