Meanwhile, the Hunters, now co-led by the masked man Krogan and a still-living Viggo, make preparations for their next move. Before Johann can finish Hiccup, he is frozen by the Bewilderbeast. Toothless appears to be the only exception until he too begins to rebel, but the riders discover to be the true cause to be freshwater-dwelling parasitic dragons called Grimoras. Dagur fires a boulder, from a catapult, onto The Reaper causing the ship to sink, leaving Hiccup with a choice: Retrieve the device he found from Dagur, or save his friends from certain death. Each time you have to fight back the villains attacking the local fields and towns, but the main character Hiccup and his faithful companion named Toothless ready to defend! They identify the rider's dragon with the Dragon Eye as a Razorwhip and pursue it to a remote island. Gruffnut is revealed to owe money to the Hunters and promised one of the riders' dragons to pay off his debt.
They discover that the village has been overrun by Speed Stingers, a non-flying dragon that move at blindingly fast speeds and can paralyze their victims with their tails. With no metal, and therefore no weapons to protect their village, Hiccup and the others must find a way to get rid of the rogue dragons, only to discover that the Smokebreaths' appearance was planned as an attack by Dagur the Deranged. When Hiccup attempts to take out Heather, Astrid intervenes and tells him and the others about Heather's plan to learn about the hunters' real leader, Viggo Grimborn, whom everyone is afraid of. Snotlout uses the Smothering Smokebreaths to get it back and the riders help the Armorwing when they pick apart its hide, earning its trust. Upon landing there, they find the island has been taken over by a massive new dragon called the Catastrophic Quaken.
Upset over his father's lack of faith of him, Snotlout tosses the axe in anger down on an island where it is found stuck to the magnetic hide of a new dragon — the Armorwing. Later, an injured Heather and Windshear return from Vanaheim with dire news. They investigate only to be imprisoned by a dragon-worshiping tribe called the Defenders of the Wing led by Queen Mala, who believes them to be hunters for their subjugation of dragons. The twins hold a funeral for Macey back on the Edge, where Tuffnut reveals stolen schematics that leave the riders worried for what 'Project Shellfire' entails. Krogan is captured and executed by his employer, Drago Bludvist, for his failure in acquiring the egg and Drago begins to seek out a new Bewilderbeast.
Before leaving, Alvin arrives with reinforcements to help keep Berk safe while Stoick is recovering. Once out of the cave, the Riders destroy the Flyers' facilities and free the Singetails. The three trust the Fire Terrors to take the Eruptodon egg and it safely reaches the nesting ground where it is bathed in the lava. Determined to win back Dark Deep for the Gronckles, Fishlegs allows Snotlout to train him in fighting dirty behind Hiccup's back in order to beat the Quaken and drive it off, but quickly find themselves outmatched once they confront it directly. Hiccup wants to take the chance to enact revenge on Viggo for his underhanded attack on Berk without a plan, but is caught up investigating and surviving the aggression of a small pack of new dragons and their leader that have driven the Hunters from their observation post. De Marco January 8, 2016 2016-01-08 Spitelout comes to Dragon's Edge to announce a union between the Jorgenson and Hofferson clans and charges last pick Snotlout with delivering the Jorgenson family axe to the Isle of Frigga for the ceremony. One by one the riders cure their dragons using salt water, and agree to take vacations at home while Hiccup promises to lighten up on his Viggo obsession.
When the riders find Ryker, he tells them that Viggo is setting them up and he can give them the Dragon Eye as the Berserkers are attacked by the Shell Fire, a giant sea dragon equipped with Hunter weaponry. Blinded by their grudge against each other, Toothless runs away to confront the rival alone. They eventually learn the Rumblehorn has been attempting to warn everyone of an approaching tsunami and chase them off before the wave would wipe them all out. The Speed Stingers have trekked across the frozen sea to Berk and driven everyone out of town. Noting that this dragon is an undocumented species, he takes it in for care and closer study. We go with you once again to the beloved by many viewers island of Berk. Sullivan John Tellegen June 26, 2015 2015-06-26 Hiccup manages to rescue Heather, and though she is still determined to take revenge, Hiccup persuades her to leave it for another day.
With Spitelout's help, Hiccup discovers weaknesses in the Singetails' behaviours while the Riders, Stoick, the A-Team, and the Berk fleets launch a preemptive strike on Dragons' Edge where the Hunters are. Together they meet with Johan who reveals Dagur's plans to purchase new dragon-proof ships and weaponry, and they convince the riders to launch a surprise attack. Hiccup and Fishlegs face continuous difficulties working together to deliver the egg, and things are made worse when a pack of wild Fire Terrors inhabiting the cave kidnap the egg. Sullivan John Tellegen June 26, 2015 2015-06-26 Back on Berk Stoick has asked the riders to deal with a Scauldron which is in the waters around Berk. Though he leaves with a seemingly empty chest, it is revealed to secretly contain a Dragon Eye lens, though Gruffnut remains ignorant to its significance. However, Dagur betrays Alvin, claiming that because the Skrill is the Beserker's emblem, that they have full control over it, and gets rid of him.
The Death Song rejects Garffiljorg when it sings the songs taught to it by the riders and imprisons them, but Garffiljorg returns to protect them by singing the Death Song's native cry. Soon enough Hookfang is in deep trouble as his flame goes out, so it's a Race to Fireworm Island to help restore Hookfang's flame before it is too late. So with the help of Fishlegs, Hiccup, and their dragons they discover that the dragon uses a paralyzing mist to attack and plan to drive the Flightmare away. When the baby dragons are forced to live on Dragon Island after nearly destroying Berk, the group learns they can't survive without a parent, so Stoick releases Thornado so he can take care of them, the two parting reluctantly. After discovering that the Bork notes are fakes made by the Outcasts, the duo tries to flee, but are captured by Alvin.
After much effort they finally get it open and Hiccup is able to retrieve the device from a distracted Dagur. It is revealed that Heather is acting as a spy and she gave Astrid the information, but when Astrid proposes that they tell Hiccup the truth, Heather declines. Meanwhile, the wounded Singetail wakes up on the Edge and despite Fishlegs' attempts to care for it, it escapes and Fishlegs and Meatlug follow it. In the end, the twins, who have been pranking everyone without end, receive retribution by the rest of the riders. As a result, Barf and Belch become indebted to Hiccup and relentlessly follow him around and dote on him, prompting the twins to come up with ways to put Hiccup in danger so their Zippleback will save him and return to them. A trade takes place, but Gustav decides to stay with Dagur.
They learn the tribe is guarded by a lava-eating dragon, the Eruptodon, whom Mala and the others label 'The Great Protector,' but Hiccup soon realizes when the Eruptodon is captured that Viggo was using them as a distraction. Johann convinces Heather to go through with the trade and though Krogan attempts to double cross her with a fake key, they are saved by Hiccup, the Riders, and Dagur, who finally reveals the truth of Oswald's fate and grants her closure. Just as they are about to celebrate his graduation, Savage and a faction of Berserkers start a revolt and imprison Dagur and the dragons. The new map displays the location of a port the hunters are on their way to, and though at first the attack is successful, Ryker reveals he is one step ahead. Snotlout and Ruffnut kidnap the Stinger and take it back to its pack when they and the rest of the riders are attacked by the other Speed Stingers who have similarly evolved. The three escape the island, but Hiccup is still not sure what to make of this old enemy turned ally.