|“||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 on patrol when they spot a seemingly abandoned fishing boat and check it out. Astrid then hears moaning coming from the boat and checks for anyone in there. As she lights a torch and heads down a hall she is horror-struck at the sight before her (the boat was a plague ship), and a pale green hand grabs her arm and scratches her before Astrid runs.
Astrid returns to the Edge silent and informs the other Riders what she saw; the men on the boat were all sick with a deadly disease. Before Hiccup can go out to help any survivors, Astrid informs him 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 and 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. And Astrid continues to try to tell everyone she's fine when she collapses, luckily Hiccup catches her and she still claims to be okay.
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 poo 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 who is surprisingly calm especially when Hiccup is so close by it. Hiccup begins to collect Buffalord saliva but it dries up before he can get on Toothless to take off. So he tries to rope him and attempts to get the Buffalord to come back with him to Dragon's Edge, but the Dragon Riders soon learn about the dragon's abilities as the Buffalord becomes enraged it begins to inflate and blow fire at them before returning to his plains where he deflates and is calm again. They notice that he refuses to leave his home, so Snotlout says if they can't take the Buffalord to Astrid, bring Astrid to the Buffalord.
Snotlout comes back with Astrid who falls off and Hiccup catches her. Hiccup sees she's now pale and weak, almost near death. He tells her to keep fighting and promises that she'll get through this, he carries her over and sets her on a rock to rest, Hiccup then tells her 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 inflates and begins to sink the ship. Viggo, realizing that Hiccup knew about the inflation, demands Ryker to release the dragon who flies back to his plains and deflates again.
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 out of respect. 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.
- 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.
- 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)