Viking and Dragon alike are starting to become tired and irritable from excessive work, so the group heads out to a remote island to relax and unwind, but there's trouble in paradise when the dragons begin to revolt against their masters.
Tropes:
- Apple of Discord: The dragons that went into the lagoon get infected by parasites that make them go feral and attack their riders.
- Broken Aesop: The way the riders talk, the moral of the episode is "overwork is bad — take a break when you need it and let your friends take a break when they need it." Hiccup deserves major credit for not pointing out that had they not insisted on taking a vacation, or had they not gone swimming when he wanted to gather limestone, the dragons never would have gotten infected by the Grimora. Contrary to what the episode's dialogue claims, the conflict of the episode happened because of the riders' desire to relax, not because of Hiccup's drive to keep working.
- Call-Back:
- The twins have to dump buckets of water on their dragon's heads, just like they learned in training in the first film.
- The spot Astrid scratches under Stormfly's chin is the same one where Hiccup scratched in the first movie.
- Call-Forward: The Hooligan dragons are being turned against their riders, which will happen later when Drago takes control of them.
- Dead Pet Sketch: When Chicken is seemingly eaten by Skullcrusher, both Stoic and Gobber independently try to replace it, but Tuffnut isn't fooled by either.
- Dramatic Irony: Hiccup is working himself and everyone else ragged desperate to protect the Dragon Eye key from falling into Viggo's hands, not knowing Viggo has already worked around needing the key.
- Foreshadowing: Toothless doesn't go for a swim, so he doesn't get infected until he and Hiccup get knocked into the water later in the episode.
- Mind-Control Eyes: The infected dragon's pupils shrink into slits, and they begin foaming at the mouth in their respective fire colors.
- Never My Fault: Snotlout, Astrid, the Twins, and Fishlegs don't admit that their dragons got infected because they wanted to relax; instead, they blame Hiccup for overworking them and their dragons that caused them to go on the vacation in the first place.Fishlegs: You know, this is really Hiccup's fault if you think about it. Shouldn't you be mad at him? Help! Somebody! Anybody! Whoa!
Hiccup: They chewed off their saddles to get the Grimoras off of them. Not because they were rebelling. See? And you thought I was working them too hard. (Everyone, including Toothless, gives Hiccup angry looks) - Salt Solution: This is how you defeat a Grimora.
- Too Much Information: While noting that Hookfang won't eat the super salty meal the twins made, Snotlout feels the need to explain that he's seen his dragon eat piles of fresh yak dung. The others stop him while he's trying to go into detail.
- Weaksauce Weakness: The parasites can't handle salt. Even sprinkling it on a dragon they've infected is enough to make them flee.
