Dragons: Alliances on Berk

Peace has finally come to the Island of Berk. The Outcasts and Hooligans are united, Dagur is in a cell, and Hiccup and Astrid are finally starting to admit more of their feelings toward one another; but what happens when an old enemy that was seemingly defeated somehow returns? It's going to take the Defenders of Berk, the Outcasts and an unlikely 3rd party to defeat this old foe.