When Alvin the Treacherous captures the Skrill, Hiccup, Ruffnut, and Tuffnut go undercover to discover that a truce is in the process of being formed between the Outcasts and the Berserkers to invade Berk with the Skrill as their weapon. Dagur is giving Alvin the support of his vast fleet in exchange for the Skrill, but the truce is uneasy. The trio must now flee to release the Skrill from their control before the truce can be settled. However, Dagur betrays Alvin, claiming that because the Skrill is the Beserker's emblem, that they have full control over it, and gets rid of him. Dagur then attempts to take on Hiccup and Toothless with the Skrill, but he doesn't have Hiccup or Alvin's experience with dragons and the dangerous Skrill proves more than either of them can handle. Hiccup and Toothless manage to lure the Skrill into a glacier, freezing it once again.
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Complete story — includes the ending
When Alvin the Treacherous captures the Skrill, Hiccup, Ruffnut, and Tuffnut go undercover to discover that a truce is in the process of being formed between the Outcasts and the Berserkers to invade Berk with the Skrill as their weapon. Dagur is giving Alvin the support of his vast fleet in exchange for the Skrill, but the truce is uneasy. The trio must now flee to release the Skrill from their control before the truce can be settled. However, Dagur betrays Alvin, claiming that because the Skrill is the Beserker's emblem, that they have full control over it, and gets rid of him. Dagur then attempts to take on Hiccup and Toothless with the Skrill, but he doesn't have Hiccup's experience with dragons and the dangerous Skrill proves more than either of them can handle. Hiccup and Toothless manage to lure the Skrill into a glacier, freezing it once again.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, List of DreamWorks Dragons episodes. HTML formatting and reference markers removed. · Content license