After an attack on Berk, Astrid trains a crew of backup Dragon Riders to battle back - but no one can guess how soon the next strike will hit.
A new enemy named Ryker Grimborn captures Stormfly, sending Hiccup, Toothless & the team off to rescue her before it's too late.
As Hiccup & Snotlout race to rescue the others from the Dragon Hunters, they don't realize that someone close to them is working with the enemy.
After a strange creature bites Tuffnut, he believes he'll turn into a legendary Lycanwing dragon when the moon is full. Can his friends save him?
Snotlout & Astrid must deliver a special battle axe to a family wedding, but when an Armorwing dragon derails their plan they have to work together.
After Hiccup & Toothless heroically save Barf & Belch, the grateful Zippleback tries to repay its life debt by abandoning riders Ruff & Tuff.
Ryker is determined to create a key to the Dragon Eye, so he heads to Glacier Island to find the Snow Wraith that the Dragon Riders are protecting.
When Ruffnut is captured by Dragon Hunters, it's up to Astrid & Tuffnut to defend Dragon's Edge from the invading Dragon Hunter army.
Unaware of the war on Dragon's Edge, Hiccup, Snotlout & Johann discover an island full of dragons that have been wounded by the Dragon Hunters.
When a new dragon is found in Edge Cove, the Dragon Riders must help the Sea Shocker escape a group of hungry Scauldrons.
The Skrill returns with a grudge against Hiccup & Toothless, and the Dragon Riders must choose a new course of action to stop the vicious dragon.
Hiccup & Astrid race to stop the Dragon Hunters from tracking the Flightmare after Heather spills secrets from Viggo Grimborn.
After Heather & the Flightmare have been captured by Viggo & the Dragon Hunters, Hiccup must hatch a plan to outwit the dangerous new enemy.