Episode Title:Dire Straits.Episode Description:To deal with the riders' growing resistance, Viggo captures the Submaripper, an extremely powerful and territorial Tidal-class Dragon, to create man-eating whirlpools to block all trade routes and leave Berk to wither away in starvation. Hiccup develops a diving bell to dive underwater and Changewing Acid to dissolve the chains, but the Hunters' interruption wakes the sleeping Submaripper. Hiccup still manages to free the Submaripper, and it rescues him just as the bell shatters, leaving Ryker to take a desperate Viggo away just as the other riders close in. Though Hiccup feels guilty for driving Viggo to make such a move, Stoick expresses confidence that he and the others will always be able to stop him.