Shell Shocked: Part 2. Even with the Eye returned, Hiccup and the others still refuse to trust Viggo and imprison him just as Ryker arrives with the Hunters' fleet. The riders find out the Hunters are forcing the Shell Fire to attack but are unable to get close as the attacks trigger the Edge's volcano. Hiccup rescues Viggo from his burning cell and agrees to work together to stop Ryker by using the Submaripper, the Shell Fire's natural enemy, to destroy the fleet while the Defenders' baby Eruptodon helps control the volcano's lava flow. The Shell Fire is freed and Ryker is consumed with the fleet by the Submaripper, while Viggo turns on Hiccup threatening to kill Astrid in exchange for the Dragon Eye, but Hiccup throws the Eye into the volcano and Viggo rushes to his doom chasing after it. Hiccup and Astrid realize their relationship compromises their mission and promise to remain professional as the other riders finally learn their secret. Just as they leave, however, the volcano erupts.