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.

The Outcast leader, Alvin, is kidnapped and held for ransom by bandits. They call on the Dragon Riders to request the assistance of Thor Bonecrusher.

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.

Viggo gets angry at the dragon riders continually interfering with his business and uses a deep sea dragon, the Submaripper, to control Berk's trade.

During the week of the Midnight Sun where the sun doesn't set for a week, Hiccup must deal with sleep deprivation and a dangerous new dragon.

Hiccup and the Riders, with help from Dagur hatch a plan to steal Berk's gold back.

When the Eruptodon can't take its egg into the Great Volcano, Hiccup and Fishlegs must go into the dangerous volcano with the egg before it's too late.

When the Twins journey to the Northern Markets to fix their prized mace, they end up stumbling onto a secret project by Viggo and the Dragon Hunters.

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.

The Riders learn of Ryker's attack on the Edge and attempt to stop the Shellfire and keep the Dragon Eye from being reclaimed by the Hunters.

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 from an unfamiliar creature with strange and slimy powers.

When things don't go well while Fishlegs is in charge, he gets another chance to prove he has what it takes to be a leader.

When a mysterious dragon attacks Spitelouts storehouse, Spitelout and Stoick have different ideas on what to do next.

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.

When the Dragon Riders fly to an island on a vacation, a small creature there has a special effect on the 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 are kidnapped and Toothless is forced to fight other dragons for entertainment, the rest of the dragon riders must save them before it's too late.

The dragon riders take a dragon egg from the dragon hunters and they try to train the baby dragon. Will they be able to do it?

Viggo is building an impenetrable fortress that even dragons can't break through, it's up to Hiccup and the gang to stop him.

Heather's brother Dagur shows up out of no where and asks Hiccup for help finding her. He wants to learn to ride dragons. Dagur sees Heather on the edge and goes the extra mile to protect her.

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.

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 tidal class dragon, the Sea Shocker, is found in Edge Cove, the riders must help it escape a group of hungry Scauldrons and reunite it with its migrating pod.

The Skrill returns with a vendetta against Hiccup and Toothless. Hiccup and the 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.

During their search for the escaped Dagur the Deranged, Hiccup and the Dragon Riders discover a mysterious object—one that holds their destiny.

Hiccup, Toothless and the dragon riders journey to Glacier Island in search of the Snow Wraith, a fearsome new 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, never-before-seen dragon that threatens to trap them forever.

On an island that will make the perfect outpost, the dragon riders discover its indigenous residents are a mysterious new breed of dragon.

Thinking he's allergic to his best friend Meatlug, Fishlegs gets hypnotized – and wakes up transformed into an invincible warrior known as Thor Bonecrusher.

When Dagur the Deranged captures young Gustav, it's up to Hiccup, Toothless and the dragon riders to get him back.

Fireworm dragons invade Dragon's Edge, while Ruffnut and Tuffnut discover that they have an unexpected connection to the island.

As a Rumblehorn dragon 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 new 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.

A familiar face joins ranks with the dragon riders, but it's not an easy alliance, especially when Hiccup uncovers a shocking secret about the new member's true identity.

Hiccup, Toothless 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 best friend forever.