When the twins fly to the Northern Markets to get Tuffnut's mace fixed, a chance turn of events lands them inside a secret dragon hunter operation.
Tropes:
- All Your Powers Combined: In order to destroy dragon proofed chains, it takes the combined firepower of a Gronckle, Monstrous Nightmare, Deadly Nadder, Night Fury and Zippleback.
- Defiant to the End: Ryker hovering over Ruffnut and Viggo pointing his sword at her. She just tells Viggo to take his best shot.
- Friend-or-Idol Decision: Ruffnut tells Tuffnut that the safety of the Edge and Berk is more important than Macey. Tuffnut doesn't want to hear it at first, but he ultimately decides to abandon Macey to steal plans for Viggo's new ship and later sacrifices Macey so the other riders have time to escape.
- Foreshadowing:
- When Project Shellfire is revealed at the end of the episode, it shows a dragon-proof ship that can submerge itself. But there's a rather draconic outline beneath the water, suggesting there's more to it.
- During the experiment to destroy a dragon proof chain, it just had a Night Fury, Nadder, and a Gronckle blast to heat it up. It is later revealed that it only needs a Nadder and Gronckle blast to do it.
- The blueprints Tuffnut has feature a person holding a bullhook. Think who else has a bullhook.
- Logical Weakness: Yes, Changewing acid works on dragon-proof metal, but it's both very dangerous to obtain and just as dangerous to carry around, leaving the riders looking for another, more reliable method for destroying the metal.
- Maybe Magic, Maybe Mundane: The twins claim their "twintuition" will lead them to the solution of any problem, though it looks like just doing whatever crazy thing they want to whenever they want as usual - so everyone is obviously skeptical. But then, every single choice it leads them to make puts them down a path of increasingly perfect coincidences, even if it doesn't seem so at first, resulting in every problem the Riders had - and even one they didn't know they had yet - being solved. The big joke is whether they're just blundering and getting lucky like Hiccup thinks, or whether they really are intuitively picking the right thing to do as they said all along.
- Twin Telepathy: Ruff and Tuff claim they have this in the form of the titular "Twintuition". Although they seem to be exaggerating, a captured Ruff does seem to sense Tuff's presence before he actually appears.
- Viking Funeral: The twins hold a mini one for Macey, but being the twins, miss completely with the burning arrow. Toothless has it covered.
- Wrecked Weapon: Tuffnut puts a big crack into Macey trying to use it to break dragon proof metal chains. Although he is able to repair it, he ultimately uses it to jam a mechanism to give the others time to escape, which shatters it completely.
