|“||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 Toothless attempt to free Heather and Windshear while under heavy fire. They try to break the chains by blasting it with plasma blasts but discover they are dragon-proof. Thinking wisely, Hiccup and Toothless decide to destroy the winches, which are not dragon-proof yet and frees Heather and Windshear. Hiccup tries to convince Heather not to go forward with her mission as he sees it to be suicide. Heather tries to justify that she came too far and might not be able to have this chance again and is willing to do anything, but Hiccup convinces her to stop after he asks if she is willing to sacrifice her dragon also, and promises that there will be another time.
Though reluctant, Heather is convinced and exits the scene. While they head back to the Edge, Hiccup notices Heather is still upset and informs her that he knows what happened to her village that Dagur 'wiped' out and her parents' death. Heather ends up revealing that she was separated from her birth family when she was very young, meaning the ones who died wasn't her true parents. Though she does not remember much, she does remember a few short moments with her true family. Such as she remembers how her father's hands felt when they touch hands, the smell of her father's wooden shield which she thinks she wasn't allowed to play with it. Another one is a horn her father gave to her. Although she doesn't know what it means, the horn is the only reminder she has left of her father.
After arriving at Dragon's Edge, Heather apologizes to the Riders for locking up their dragons, using the excuse that she thought she couldn't trust them if she told them that she was going after Dagur. Her apology is quickly accepted and while Heather is overwhelmed by their hospitality, she is also annoyed by her personal space being invaded. Astrid ends up pulling her away from the scene and invites her along for some girl time.
While throwing axes and discussing clever fighting tactics, Heather and Astrid briefly talk about the male Riders. Astrid claims she and Hiccup are just friends even though she finds him to be heroic and unassuming. She teases Heather about Snotlout but Heather reveals that she is more into little smarts like Fishlegs. She thinks he is cute and funny. Astrid doesn't seem to share her sentiments though. They spend the remaining of the time jumping over a cliff until Heather invites Astrid along to her old campsite to look for 'something'.
They end up meeting up with Trader Johann who is first spotted by Astrid. He appears to be concerned for Heather's well being and is relieved to see her again. Heather reveals that she has been using Johann to keep track of Dagur's location. Johann informs them of Dagur's plans. He is preparing to gather more ships equipped with dragon-proof winches and heavily armed dragon-killing mechanisms.
Meanwhile in the Dragon Stables, Toothless snoops through Heather's belongings, causing her father's horn to fall out of her bag. Hiccup notices that his father's seal is carved on her horn and begins to grow suspicious again. He ends up making a journey back to Berk to ask his father about the origin of the horn. Stoick observes the seal and explains that when a chief has a newborn child, that child receives numerous gifts from tribes all over. This leads Hiccup to wonder if Heather is his long-lost sister.
Meanwhile, Heather fails to convince the Riders to join her on a mission to hunt Dagur down. The Riders don't want to leave without Hiccup and Toothless, especially considering Toothless is the most powerful dragon in the academy. Heather is disappointed by the lack of support and ends up guilt tripping Astrid. She and the Riders end up agreeing to come along as long as Heather promises that it is a capture mission and not a kill mission. Astrid decides to leave a map behind in case Hiccup wants to find them.
While Snotlout, the Twins, and Fishlegs act as diversions, trying to draw the attention to themselves, Heather and Astrid sneak aboard Dagur's ship and use 'the element of surprise' to take his men down, one by one. They eventually manage to capture Dagur and tie him up. Despite her promise to Astrid, Heather tells her dragon to finish Dagur off.
Astrid tries talking her out of it but it is to no prevail. Heather still wants her revenge. Just as Windshear prepares to kill Dagur, Hiccup arrives the scene and orders Heather to stop. Heather remains determined to kill Dagur until Hiccup tells her the truth about her horn. He starts by explaining that it has his father's seal carved on it. Heather, surprised, asks him to elaborate. Hiccup ends up revealing that Heather is the daughter Oswald the Agreeable, the chief of the Berserkers. This means that Dagur is her brother.
Heather is stunned by the revelation of her identity. The rest of Dagur's ships soon being to arrive to reinforce the attack against the Riders. Dagur manages to break free from his ties and offers Heather to join him as he is the only 'family' she has left. Heather declines his offer and leaves with the Riders.
Later that evening, Heather is getting ready to leave the Edge with Windshear. Astrid tries talking her into staying but Heather explains that she needs some time alone to figure herself out. She is thankful to Astrid for her friendship though.
Hiccup arrives just before Heather flies off. He offers her a chiefly nod as a goodbye gesture. Once Heather has taken off, he turns to Astrid and tells her that he is sorry she is losing her friend. Astrid responds by pulling him close to her and telling him at least she still has him.
- Dagur indicates he might have already known that he and Heather were siblings-
- In a previous episode "The Night and the Fury", he mentioned he has a sister, and how she had a shield like Hiccup's. Ironically, one of Heather's earliest memories was of a shield.
- He calls to Hiccup "it wouldn't be a family reunion without you!" when a "reunion" typically involves three or more family members, so Heather must be the third.
- Right before Heather gags Dagur and Hiccup stops her from killing him, Dagur says "If you kill me, Heather, you'll never know . . . (gag)". It's likely he was about to tell her that they're siblings.
- When Hiccup tells Heather that Dagur is her brother, she's totally shocked while Dagur didn't look the least bit surprised.
- Heather reveals she was adopted.
- In one of the flashbacks, she is shown playing with her father's shield, a boy can be heard laughing and runs in front of her. It's possible that the boy was a young Dagur.
- Heather's birth father is revealed to be Oswald the Agreeable, making Dagur the Deranged her brother.
- After Hiccup tells Gobber he needs to talk to his father, Heather's horn is missing from his hand.
- Dagur says that he is the only family Heather has left, hinting that their mother may also be deceased.
- In one scene, Heather's hooded shirt is missing.
- When Heather talks about sending Dagur back to Outcast Island, the lens is on her belt.
- When Hiccup and Toothless fly and don’t see the riders, the map is missing on the wall.
- The Romantic Flight cue is heard at the end of the episode when Hiccup and Astrid share a sentimental moment.
- During Heather's flashbacks of her early childhood, Dagur can be seen running across and laughing mischievously.
- When Heather says "hit him when he least expects it," her braid is transparent at the top.
- It is possible the "undesirables" that Dagur purchased his new weaponry from are the Dragon Hunters, which would later lead to his alliance with them.
- Jay Baruchel as Hiccup Horrendous Haddock III
- America Ferrera as Astrid Hofferson
- Nolan North as Stoick the Vast
- Christopher Mintz-Plasse as Fishlegs Ingerman
- T.J. Miller as Tuffnut Thorston
- Andrée Vermeulen as Ruffnut Thorston
- Zack Pearlman as Snotlout Jorgenson
- Mae Whitman as Heather
- Michael Goldstrom as Johann
- Tom Kenny as Silent Sven
- Hiccup's Prosthetic Leg
- Toothless' Saddle and Tail Fin
- Astrid's Old Axe
- Astrid's Kransen
- Heather's Axe
- Heather's Horn
- Heather's Dragon Eye Lens
- Dagur's Ship