To prove they're on the same side and pose no threat, the Dragon Riders try to rescue Queen Mala's dragon, which Viggo stole to destroy Dragon's Edge.

Tuffnut is eager to impress his visiting cousin, Gruffnut. But Ruffnut is suspicious of his real reasons for coming to Dragon's Edge.

The Dragon Riders attend Berk's 400th anniversary celebration, where a bounty on Hiccup's head casts a dark shadow over the festivities.

After getting bad advice from his father, Snotlout tries to seize leadership of the Dragon Riders and starts making reckless decisions on his own.

Hiccup and Heather are shocked to see Dagur among the Dragon Hunters. Snotlout undergoes the Trials, a series of tests he must pass to be Mala's king.

Viggo gets angry at the dragon riders continually interfering with his business and uses a deep sea dragon, the Submaripper, to control Berk's trade.

During the week of the Midnight Sun where the sun doesn't set for a week, Hiccup must deal with sleep deprivation and a dangerous new dragon.

When the Eruptodon can't take its egg into the Great Volcano, Hiccup and Fishlegs must go into the dangerous volcano with the egg before it's too late.

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.

While rescuing the dragons from a fire in the stables caused by a powerful lightning storm, Astrid suffers an injury that leaves her blind.

After months of planning, Hiccup launches an operation to capture the Dragon Eye from Viggo, only to find that someone else has beaten them to it.

The Riders learn of Ryker's attack on the Edge and attempt to stop the Shellfire and keep the Dragon Eye from being reclaimed by the Hunters.