Shell Shocked, Part 1. Animated series. Hiccup doesn't know who to trust when Viggo and Ryker each tell him that the other has gone rogue, and is sidetracked when a dragon attacks. [S]
Twintuition, Part 1. When the twins journey to the Northern Markets to fix their prized mace, they end up stumbling onto a secret project by Viggo and the dragon hunters. [S]
Gold Rush, Part 1. Animated series based on How to Train Your Dragon. Hiccup and the Riders, with help from Dagur, hatch a plan to steal Berk's gold back. [S]