Alvin reveals he trained the Screaming Death to attack Berk and destroy the island's inhabitants and only Snotlout and Hookfang can save Berk before it's too late. Meanwhile Hiccup gets ready for a final fight against Dagur to save Toothless and end the barbarians invasion of Berk once and for all.
Elenco: Jay Baruchel , America Ferrera , Christopher Mintz-Plasse , T.J. Miller , Zack Pearlman .