Hiccup and Astrid race to stop the Dragon Hunters from tracking the Flightmare after Heather spills secrets from Viggo Grimborn.

After Heather and the Flightmare have been captured by Viggo and the Dragon Hunters, Hiccup must hatch a plan to outwit the dangerous new enemy.

After Astrid makes an alarming discovery, her life comes to depend on a dragon everyone thought was extinct. Her pals race against time to find it.

Viggo is building an impenetrable fortress that even dragons can't break through, it's up to Hiccup and the gang to stop him.

Snotlout is sent on an undercover mission to Viggo's dragon auction as part of a plan to rescue the dragons and stop Viggo from getting richer.

When Viggo offers Hiccup a truce, the wary Dragon Riders investigate and find a potential ally in their fight against the Dragon Hunters.

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.

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.

Hiccup and the Riders, with help from Dagur hatch a plan to steal Berk's gold back.

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.

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.

The Outcast leader, Alvin, is kidnapped and held for ransom by bandits. They call on the Dragon Riders to request the assistance of Thor Bonecrusher.

After the Edge is ambushed by a group of Singetails, the Riders quickly take flight to ward them off, but are shocked when they get a closer look.

The Riders flee to Berk, where Stoick's plan for defeating the Flyers, which will require a painful sacrifice, spurs Hiccup to seek an alternative.

An unlikely ally helps Hiccup uncover Singetail behaviors that can be exploited to conquer the Flyers. An overconfident Krogan makes a strategy error.

When Heather goes to meet a man claiming to have seen Oswald, she walks into a trap that forces the Dragon Riders to pay a dear and unexpected price.

While hunting for gemstones needed to complete the Dragon Eye 2, Hiccup learns an old friend isn't who he seems. Dagur faces a bully from his past.

When the Flyers try to kill him because he's no longer useful, Viggo forces Hiccup to help him get revenge by stealing their Dragon Eye and lenses.