"Hiccup and Toothless have discovered a rare and deadly Skrill, a dragon that flies through the clouds and fires lightning at its enemies. When the terrifying dragon is unleashed, they've got to scramble to get it off Berk. But that's not all they're up against. Dagur and his army of Berserkers also want to find that Skrill and train it as a weapon to use against the Vikings of Berk" --,Page 4 of cover.