|“||We're gonna beat this. I promise you, Astrid. You just have to keep fighting and hold on. You need to stay with us. I can't imagine a world without you in it.||”|
|“||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.||”|
The episode opens with Astrid and Stormfly enjoying an early morning patrol of the Alpha Quadrant, when they spot a seemingly abandoned fishing boat and fly in to check it out. Astrid then hears moaning coming from the boat and decided to check if anyone is in there. Stormfly lights a torch and Astrid heads below deck, Stormfly poised to strike behind her; what she sees causes her to react in utter horror. A hand with pale green skin, reaches up and clamps onto her arm, scratching her. Astrid gasps in horror and fear, fleeing the boat instantly.
Astrid returns to the Edge silent and sullen, and informs the other Riders of what she saw; the men on the boat were all sick with a deadly disease. Before Hiccup can go back to the boat to help any survivors, Astrid informs him bleakly that it's too late as they were all dying or dead when Astrid saw them. The deadly disease is known as the Scourge of Odin, a plague that has wiped out Vikings centuries ago. Hiccup questions Astrid's behavior as she is quieter than usual. Astrid assures him that she's fine but looks unsure herself. That night, Hiccup and Toothless are woken up by Stormfly who is worried for her Rider and leads Hiccup to Astrid's hut, where he sees Astrid is not feeling well; lying on her bed and continually coughing. Hiccup finally notices the scratch from the ship. Fishlegs is checking all her symptoms the next morning and tells Hiccup that she might have gotten the Scourge of Odin. Snotlout comes from Berk with Gothi's notes on the Scourge of Odin, and the three find out that the cure for it is "a green solution from the Buffalord dragon". Fishlegs and Astrid tell Hiccup that there aren't anymore Buffalords as they were hunted to extinction during the last outbreak. Fed up of everyone fussing over her, Astrid gets up to remonstrate once more that she's fine, looks a little faint, then collapses, being caught by Hiccup.
Hiccup leaves Astrid to rest, Fishlegs tells him he found information on the Buffalord but no location is shown. The Twins find pieces of paper with lines and other symbols on it that Fishlegs copied from the Dragon Eye, and they piece together a map that shows where the Buffalord is located. Hiccup matches it up with his own map and hopes that it still exists. The Riders land on the island where the Buffalord lives but so far find a pile of dragon droppings with an unusual smell. Fishlegs says that it belongs to the Buffalord, that it has a vegetarian diet and it's still fresh. Hiccup uses Flightmare algae to track the Buffalord's footprints but when the tracks stop Hiccup finds one of its scales meaning it's not too far.
They finally find the Buffalord and approach it cautiously, reasoning that it will likely not be happy to see humans after being driven to near-extinction. Surprisingly, the beast is incredibly docile and barely even reacts to their presence. Hiccup begins to collect Buffalord saliva but it dries up before he can get on Toothless to take off. Hiccup decides to rope the dragon and lead him back to the Edge. The Buffalord, whom Snotlout names Big Buff, doesn't react at all as it is roped up for transportation; Fishlegs notes that for such a large dragon it is surprisingly peaceful, while Snotlout remarks that it must be why it was so easily hunted and advises it to toughen up. The Buffalord, after some initial reluctance, takes to the air with the Riders but as it gets further away from the island, the dragon suddenly goes berserk. The Buffalord breaks the ropes by inflating and launches spines and exploding flames in all directions, forcing the Riders to scatter. The Buffalord lands back on the island and returns to it's usual docile demeanor, but it's clear to the Riders that it will not be leaving unless it wants to leave and will probably kill them if they try to make it, so the only option is to bring Astrid to the island.
Snotlout comes back with Astrid who falls off Stormfly and Hiccup catches her. Astrid is now pale, green-tinged and weak, almost near death. He tells her to keep fighting and promises that she'll get through this. Hiccup then carries Astrid over to the Buffalord and sets her against a rock to rest, telling her that he can't imagine a world without her in it. Hiccup begins to get the saliva again and gives it to Astrid but she doesn't get any better. Fishlegs tells him that the Buffalord's green solution is the only cure, but Hiccup mentions that the Buffalord's saliva is clear and questions what the "green solution" is. Hiccup then sees Ruffnut and Tuffnut eating the same grass the Buffalord eats and notices that their saliva is a greenish color meaning that the Buffalord needs to eat the herbs plus his saliva is the cure for the Scourge of Odin, which is the reason as to why it won't leave the island as it only feeds on specific plants. So they try again and get it right this time until a net is suddenly thrown over the Buffalord.
Hiccup and the Riders then see Viggo marching towards them with his Hunters who thanks Hiccup for the dragon but apologizes that he won't save Astrid. Hiccup and the others defend the Buffalord and blast at the Dragon Hunters but soon pull back to avoid hurting the Buffalord since they need him. Hiccup then demands Viggo to release the dragon to which the Dragon Hunter refuses and reveals to Hiccup that it was his fishing boat with the infected crew that Astrid found. He rediscovered or possibly created the disease and infected his own men with it so that they will infect Astrid making Hiccup find the Buffalord for him. Hiccup then attempts to have Toothless shoot Viggo but Viggo threatens to have Ryker kill the Buffalord meaning Hiccup won't get the antidote and Astrid will die as well.
Realizing what he must do to save Astrid, Hiccup offers Viggo a deal: he'll let Viggo take the dragon but begs him to let him get the antidote first as he's not leaving without the cure. Viggo accepts and Hiccup begins collecting the Buffalord's saliva and gives it to Astrid. It works quickly and Astrid's skin returns to its normal color. Hiccup keeps his end of the bargain and allows Viggo and Ryker to load the Buffalord onto his ship, knowing what the dragon will do once it's away from his grassy plains. His plan works as the Buffalord promptly destroys its cell with ease and breaks right out of the ship, almost carrying the entire craft with it until Ryker cuts the chain and frees it. The Buffalord, indifferent to the destruction it just caused, settles back down to eat.
That night, Astrid says a few words to those who had suffered the Scourge of Odin, and the Riders shoot flaming arrows at the ship, both out of respect and to eliminate the disease. After the others head back to Dragon's Edge, Hiccup realizes that Viggo unlocked the Dragon Eye somehow without the Snow Wraith key and tells Astrid they need to figure it out. Astrid then thanks Hiccup for all he has done for her today, Hiccup states it's no big deal since she would've done the same for him, Astrid then tells him that she can't imagine a world without him either and the two smile at each other before departing, leaving the ship to burn and with it, the Scourge.
- Tuffnut is implied to be aware of the healing properties of penicillin. While the drug itself is, of course, unknown to the dragon riders, he understands that his previous cold was cured by eating moldy bread (much to the disgust of his friends).
- The Buffalord makes its debut. It appears to be the first confirmed herbivore dragon.
- This is the third time we see Astrid without her shoulder pads, and the first time in Race to the Edge.
- So far, this is the only time Hiccup has completely outsmarted Viggo.
- The funeral pyre at the end is similar to the one in How to Train Your Dragon 2. It may serve as a form of foreshadowing of the events in the film.
- During the funeral pyre they say that the victims of sickness shall go to Valhalla for being brave. Although it is true that brave goes to Valhalla in Norse and Germanic mythology, but it's been made clear that it only applies to those who died in battle, especially excluding people dying of sickness and other things non-combat such as childbirth, everyday injuries, infections, accidents, murder and old age.
- The Romantic Flight cue can be heard multiple times in this episode.
- This is the closest Hiccup and Astrid have been to confessing their attraction to one another.
- Hiccup invented glare resisting goggles using Death Song amber as lenses.
- The episode's title could be a reference to the song title "Buffalo Soldier" by Bob Marley.
- Gothi's notes on curing the Scourge of Odin is actually mostly gibberish; the part that is visible on the screen reads "Ualdor, Slagathor, Brigw, Nargalzius, Rolo, Uortegor, Brandon".
- Usually, when writing is on the screen, the animators make the words/sentences make sense, probably as an Easter egg to allow watchers knowledgeable of runes to decipher what the page says.
- Jay Baruchel as Hiccup Horrendous Haddock III
- America Ferrera as Astrid Hofferson
- Christopher Mintz-Plasse as Fishlegs Ingerman
- Andrée Vermeulen as Ruffnut Thorston
- T.J. Miller as Tuffnut Thorston
- Zack Pearlman as Snotlout Jorgenson
- Gothi (mentioned)
- Hiccup's Prosthetic Leg
- Toothless' Saddle and Tail Fin
- Astrid's Kransen
- Magnifying Glass
- Viggo's Sword
- Dragon Hunter Weapons
- Dragon Hunter Ships
- Spyglass (mentioned)
- Dragon Eye (mentioned)