Hiccup must mend fences between Astrid and Snotlout when Stormfly and Hookfang start fighting more ferociously than ever. Astrid and Snotlout must grudgingly work together to find the cause of the feud, if they want their dragons to stay in the academy. Meanwhile, Fishlegs discovers Dragon Root, which could end up affecting not just Stormfly and Hookfang, but all their dragons.