While trying to stabilize the volcano that threatens to destroy Dragon's Edge, the Riders discover troubling evidence of new Hunter activity.
As the Riders investigate why traders are disappearing from the Northern Markets, Hiccup and Snotlout fall victim to a treasure-hoarding dragon.
The Riders accept an invite to Berserker Island, where their reunion with Heather, Dagur and a young familiar face is interrupted by a sudden revolt.
When Snotlout is rescued from a storm by a tribe of winged women, he thinks he's gone to Valhalla -- until he learns he's going to be their dinner.
Disobeying Hiccup, the twins follow a retiring Eruptodon to its final resting place, Vanaheim, and learn why no human has ever gone there before.
When a pair of Outcasts visits the Edge seeking the help of Thor Bonecrusher, Fishlegs allows Snotlout to hypnotize him to evoke his mighty alter ego.
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.
After Stormfly tangles with two poisonous Slitherwings while defending Garff, Astrid must risk her own life to get an ingredient to make an antidote.
When Ruffnut refuses to become Throk's bride because it would mean leaving her twin, Tuffnut fakes his own death to give her the freedom to marry.
A sketch in an old diary leads Hiccup and Fishlegs back to Vanaheim, where they help Dagur search for his long-missing father, Oswald the Agreeable.
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.
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.
Tuffnut is eager to impress his visiting cousin, Gruffnut. But Ruffnut is suspicious of his real reasons for coming to Dragon's Edge.
The Dragon Riders attend Berk's 400th anniversary celebration, where a bounty on Hiccup's head casts a dark shadow over the festivities.
After getting bad advice from his father, Snotlout tries to seize leadership of the Dragon Riders and starts making reckless decisions on his own.
Hiccup and Heather are shocked to see Dagur among the Dragon Hunters. Snotlout undergoes the Trials, a series of tests he must pass to be Mala's king.
When a dragon that causes man-eating whirlpools threatens Berk's trade ships, the Dragon Riders must remove it without getting caught in its vortex.
With his teammates grounded due to lack of sleep from the midnight sun, Hiccup tries to help a hurt dragon alone, but suddenly gets in over his head.
When Dagur appears at the Edge claiming to know where Viggo keeps his gold, the Dragon Riders fly off to find the stash and return Berk's stolen gold.
To ensure the future survival of Mala's tribe, she and Hiccup must deposit a newly laid Eruptodon egg into the deadly Grand Volcano so it will hatch.
When the twins fly to the Northern Markets to get Tuffnut's mace fixed, a chance turn of events lands them inside a secret Dragon Hunter operation.
While rescuing the dragons from a fire in the stables caused by a powerful lightning storm, Astrid suffers an injury that leaves her blind.
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.
Although Viggo keeps his promise about the Dragon Eye, Hiccup is unsure whether he can trust him as an ally against Ryker and the Shell Fire dragon.
During their search for the escaped Dagur the Deranged, Hiccup and the Dragon Riders discover a mysterious object -- one that holds their destiny.
Hiccup and the Dragon Riders journey to Glacier Island to find the Snow Wraith, a fearsome dragon that holds the key to the Dragon Eye's mysteries.
The Dragon Riders discover a lush island that turns out to be the home of the Deathsong, a massive dragon that threatens to trap them forever.
On an island that will make the perfect outpost, the Dragon Riders discover that the indigenous residents are a mysterious new breed of dragon.
Thinking he's allergic to his dragon, Fishlegs gets hypnotized. He wakes up transformed into an invincible warrior known as Thor Bonecrusher.
When Dagur the Deranged captures Gustav, it's up to Hiccup and the Dragon Riders to get him back.
Fireworms invade Dragon's Edge, while Ruffnut and Tuffnut discover that they have an unexpected connection to the island.
As a Rumblehorn wreaks havoc on Dragon's Edge, Hiccup seeks the help of Stoick, who forms an unexpected bond with the rampaging beast.
Fishlegs and Meatlug liberate the Gronckles from a menacing dragon that has encroached on their ancestral home, Dark Deep.
The Dragon Riders are surprised to discover who is behind recent attacks on nearby ships -- and to learn exactly what the ships are.
Heather joins the Dragon Riders, but it's not an easy alliance, especially when Hiccup uncovers a shocking secret about her true identity.
Hiccup and the Dragon Riders rescue a wounded Speed Stinger and take it back to Dragon's Edge, unaware of the dangers that follow.
When Hookfang is drawn to a female Monstrous Nightmare, Snotlout tries to break them up before he loses his friend forever.
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 and the team off to rescue her before it's too late.
As Hiccup and 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 and 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 and Toothless heroically save Barf and Belch, the grateful Zippleback tries to repay its life debt by abandoning riders Ruff and 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 and Tuffnut to defend Dragon's Edge from the invading Dragon Hunter army.
Unaware of the war on Dragon's Edge, Hiccup, Snotlout and 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 and Toothless, and the Dragon Riders must choose a new course of action to stop the vicious dragon.
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.
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.
Stoick and Hiccup are led on a wild goose chase in search of willow bark for medicine, leaving Berk vulnerable to an enemy attack.
During a trip to Wingmaiden Island to find a Dragon Eye lens, Snotlout challenges Hiccup’s leadership. On another island, an unlikely romance blooms.
Upset after learning his ancestors were Hunters who killed off Dramillions, Fishlegs sets out to see if he can find any of the dragon species left.
Hiccup grows wary when Gruffnut arrives on the twins' 19th birthday to administer a Thorston coming-of-age ritual involving three dangerous challenges.
An announcement leads Astrid to question her relationship with Hiccup. The Riders discover an Armorwing that has a Dragon Eye lens welded to its body.
While visiting Wingmaiden Island, a baby Razorwhip bonds with Ruffnut, who suddenly finds herself trying her hand at being a Wingmaiden.
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.
After learning Krogan is using a Deathsong to lure and subdue Singetails for his growing army of Flyers, the Riders set out to rescue the dragon.
While on night patrol, Stoick is ambushed by the Flyers and gravely injured, leaving Hiccup torn between his duties as a son and as the Riders' leader.
After learning several Flyers followed Heather to Vanaheim, the Riders must stop them from reporting the sacred island's location to their leader.
With the fifth lens in place, the Dragon Eye 2 unveils the apparent King of Dragons, and Fishlegs immediately knows what it is and where to find it.
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.
While trying to take care of unfinished business, Hiccup and Toothless are lured into a trap. An unlikely rescuer comes to their aid.
A wounded Fireworm seeks the Dragon Riders' help in protecting a precious treasure trove against an unfamiliar creature with strange and slimy powers.
When things get out of hand while Fishlegs is left in charge, he seizes another chance to prove he has what it takes to be a leader.
Hiccup's and Snotlout's fathers put aside their differences and work with their sons as a team to defend a storehouse against an unusual invader.
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.
Hiccup reluctantly allows the Dragon Riders to go to a deserted island for a much-needed vacation, but the getaway has an odd effect on their dragons.
After learning that Fishlegs has been secretly communicating with Heather, the gang invites her to the Edge to convince her to join the Dragon Riders.
When Hiccup and Toothless accidentally land in a Dragon Hunter trap, they find themselves the newest contestants in a gladiator-style arena.
Hiccup and his team rescue a dragon egg and bring it back to the Edge, where it hatches to reveal an ear-splitting surprise!
The gang investigates why Viggo's men are mysteriously shipping marble blocks from a quarry. Next, they try to save two dragons being used as slaves.
When Dagur unexpectedly shows up, Hiccup scrambles to prevent him and Heather from discovering each other's presence.
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.