When the Great Protecter can't take her egg into the Great Volcano, Hiccup and Fishlegs must go into the dangerous volcano with the egg before it's too late.
The Defenders of the Wing contact the riders for their aid in delivering the Great Protector's egg to the nesting site inside their island's volcano to hatch before it hardens to stone. Hiccup and Fishlegs face continuous difficulties working together to deliver the egg, and things are made worse when a pack of red wild Night Terrors inhabiting the cave kidnap the egg. Mala attempts to retrieve the egg herself, but Hiccup and Fishlegs regain their synergy and realize the Terrors are there to safely bring the egg to the nesting ground without human interference. The three trust the Terrors to take the Eruptodon egg and it safely reaches the nesting ground where it is bathed in the lava.