In the Dragons: Race to the Edge episode "Reign of Fireworms" (Season 3, Episode 7), the Dragon Riders face a dual threat: a natural disaster in the form of a massive dragon migration and a sudden political upheaval within their own ranks. Plot Overview
They ban the letter "S" from the alphabet, causing communication to break down. [S3E7] Reign Of Fireworms
Tuffnut assigns Hiccup the role of "stableboy," forcing him to wait on all the dragons. In the Dragons: Race to the Edge episode
As the other Riders—Astrid, Fishlegs, and Snotlout—rebel against or fail to entertain the twins, they are thrown into a makeshift dungeon. Resolution and Themes [S3E7] Reign Of Fireworms