Hiccup and Stoick set forth to find willow bark, while Gobber holds a cook-off for the merchants until things take a turn for the worst and the riders have to protect Berk.
Hiccup teams up with an unexpected person in search for an antidote when Toothless is seemingly poisoned.
When Stoick is shot down, Hiccup and the riders race back to Berk to help.
Krogen is on the hunt for dragon lenses, while Snotlout and Minden do their best to defend Wing Island. Back in Berk, Dagur and Mala feud over keeping the lenses safe.
After learning that his ancestors once hunted dragons, Fishlegs goes on a journey to find a Dramillion dragon, while being faced with the challenge to clear his family name.
The riders battle the Flyers at Berserker Island, while Hiccup and Dagur search the caves and find a Bewilderbeast egg.
The Riders think they have discovered the King of Dragons, but quickly learn along with the Flyers that the real King of the Dragons lives under Berserker Island.
The riders race to Vanaheim and discover the Flyers have ransacked the island.
Hiccup and his crew are in search of dragon eye gems, only to discover a spy amongst them! In the midst of it all, Dagur has run into an old nemesis!
Hiccup and the riders are on the run from the Flyers, but when they return to Berk, Hiccup is torn between his desire to get the Edge back and his unwillingness to fire on dragons. Show more
When Thor Bonecrusher is needed to rescue hostages taken by the Bandits, Snoutlout tries to help but accidentally brings to life Thor's evil twin, Anti-Thor, who sides with the Bandits.
After being ambushed by aggressive Slitherwing dragons on a new island, the Riders think Stormfly has been poisoned and race to get an antidote.
When Hiccup and Astrid go away for a weekend, the Edge is attacked by Krogan, Viggo, and their new Dragon Flyers.
When Stoick decides to take the battle on the Dragon Flyers to the Edge, the Riders must figure out how to trap the Flyers and take back the Edge.
With their enemies defeated and the volcano erupting on Dragon’s Edge, the Riders decide to return to Berk. However, Hiccup discovers that the Dragon Hunters are still out there.
Hiccup flies to find Heather after she is lured to the Northern Markets as a trap. However, when he arrives too late, Windshear is captured by Krogan.
On a search for Dagur's dad, Hiccup and Dagur encounter vicious Grim Gnashers,
and Tuff’s search for a missing Chicken leads him to discover she has a second family.
Tuff fakes his own death to make room for Throk, but when Ruff tries to train the Changewing that she thinks ate Tuff, a flock of angry Changewings come for the dragon.
The twins are preparing for their birthday when they are visited by a notoriously mischievous relative administering the Thorston Rite of Passage challenges.
Following the announcement of Dagur and Malas's engagement, Astrid questions her relationship with Hiccup. In the meantime, the Riders battle Krogan over an unexpectedly placed lens.