While searching for gemstones. Johann drives Hiccup to the Sandbuster's lair and Johann helps Hiccup find all the required gems and then Johann reveals his deception and demands Hiccup the dragon eye lenses.

Stoick and Hiccup argue as Stoick is determined to procure willow bark for Berk while Hiccup has a nagging suspicion that all is not what it seems. Three traders compete to become Berk's new supplier.

The Riders host a meeting on Defenders of the Wing Island to discuss the threat Johann poses, however, Dagur and Mala constantly disagree with each other's ideas. Through Ruffnut and Tuffnut's mediation, Dagur and Mala actually get along and develop a mutual attraction for one another. Meanwhile, Hiccup and Snotlout travel to Wingmaiden Island to escort Atali to the meeting, where Atali leaves her second-in-command, Minden, in charge of the island, though Minden is upset at not being allowed to attend the meeting as well. When a fire breaks out on the other side of the island, Minden orders all the guards to put it out, leaving the Wingmaidens defenseless to a surprise attack from the Flyers, resulting in Atali being injured and knocked out. Feeling guilty over her mistake, Minden, with Snotlout's aid, recovers the hidden Dragon Eye lens on their island, which the Flyers have come for. After her repeated failures, Minden loses hope and confidence in herself and quits being a ... Written by Ampm

After learning his ancestors were dragon hunters who killed off the Dramillions, Fishlegs sets out to Dramillion Island with Astrid (against Hiccups wishes) to find and help protect the Dramillions from harm. Before setting out, he remembers his dragon scouts are coming and leaves the twins to look after them. After arriving, he immediately finds one and tries to train but discovers it is very aggressive and has the unusual ability to mimic the fire blasts of other dragons, such as a Gronkle's lava blast and Nadder's magnesium fire breath. While searching the island for more, they discover a group of hunters, who are following the teachings of his ancestor, Ingard Ingerman in trapping Dramillions and using them to help train new recruits. When the hunt begins, Fishlegs and Astrid combine Meatlug and Stormfly's fire to destroy the shackle that grounds the Dramillion. Though they realize that they won't have enough time to save them all, the Dramillions learn the technique to destroy ... Written by Ampm

Hiccup grows weary when Gruffnut arrives on the twins' 19th birthday to administer a Thorston coming of age ritual involving three dangerous challenges.

While wondering what to do with loads of scrap metal, Dagur and Mala arrive on the Edge to announce that Dagur has completed Mala's king trials and are to be wed. After hearing this, Astrid starts to think that Hiccup isn't interested in her anymore since they are not as publicly affectionate as Dagur and Mala and begins to question her relationship with him. After deciding that the Armowing will make the best use of their spare scrap metal, Hiccup, Astrid (wearing Hiccup's Betrothal necklace), Snotlout, Fishlegs and Dagur go to the island to find the dragon. After landing, Dagur asks Hiccup to be his best man at the wedding while Astrid becomes annoyed that Hiccup hasn't noticed her wearing his betrothal necklace. After the Armorwing appears, Hiccup notices a Dragon Eye lens on its back. Krogan and his Flyers arrive to take and lens and succeed after the Riders choose to instead evacuate the injured Armorwing rather than pursue Krogan. Astrid apologizes to Hiccup for her anger and ... Written by Ampm

While visiting Wingmaiden Island, the Riders get to witness the ceremony where newly hatched baby Razorwhips choose their Wingmaidens. One baby ends up choosing Ruffnut, whom Atali insists must become a Wingmaiden. Though Ruffnut struggles with the tasks to care for her Razorwhip, named Wingnut, she only succeeds thanks to Tuffnut's secret assistance. Despite Atali's encouragement, Ruffnut is certain that she cannot be a Wingmaiden and that Wingnut is better off without her. When Flyers attack, Ruffnut rescues Wingnut and uses her newly learned Wingmaiden abilities to help repel the Flyers' attack. Seemingly accepting that Ruffnut's place is with the Riders, Wingnut accepts Atali as its new Wingmaiden and caretaker. Written by Ampm

Viggo is betrayed by Johann but manage to stay alive and contact Hiccup in order to plot a double-cross scheme against Johann and Krogan.

The gang realize that Krogan uses DeathSong dragon to catch more SingeTail dragons, but when they free the dragons they don't fly away and the gang try to figure out why.

In one of the Berkian patrols Stoick gets hurt, and when Hiccup heard about it he blamed himself all the way to the beginning of the Human-Dragon relationship.

The Flyers follow Heather Vanaheim and attack it, assuming the last lens is there, and leaving a great destruction. The Riders arrive just in time to clean the mess.

The Riders and the Flyers go to Dramilion island, led by the complete dragon eyes. And again, Hiccup realizes that Johann and Krogan are one step ahead of him and struggles to catch up.

The riders race to the home of the true King of Dragons. But the flyers are already there, and they soon come face to face with the legendary creature.