Hiccup decides on a plan to play on dragons’ natural asthmatic tendencies. Toothless is afraid, and Snotlout complains about putting his own dragon at risk. Hiccup orders the boys to make “feather bombs” that they can use as distractions. He then coaches Fireworm and Killer on what to say to the Purple Death and Green Death, respectively.

The Meatheads head toward the Purple Death in the Unland-able Cove while Hiccup leads the Hooligans to the Green Death on Long Beach. The smaller dragons line the green dragon’s mouth with the feather bombs, which wake him up with a sneeze when he inhales them. Fireworm, pretending to be the Purple Death’s offspring, delivers a message laced with insults and threats. She quickly flies away toward the Purple Death as the other Berk dragons slow the Green Death with feather bombs. Just as the Green Death catches up with Fireworm, the Purple Death collides with him. The Green Death releases Fireworm, and both Sea Dragons settle down in the ocean.

At Death’s Head Headland, the two Sea Dragons fight a fierce battle that changes the landscape of the island.