When the Dragon Riders learn that Ryker is headed to Glacier Island, they realize he is trying to get a Snow Wraith tooth so he can operate the Dragon Eye. The riders rush off to protect their one time enemy.
Tropes:
- Chekhov's Gun: Hiccup uses the Dragon Root arrow lodged in Tuffnut's helmet to put the Snow Wraith back to sleep. Sadly, he misses.
- Continuity Nod: Snow Wraiths return.
- Didn't See That Coming: Hiccup didn't realize Snow Wraiths could burrow through the ice. Unfortunately, Ryker did and planned for it.
- Disappointed in You: While he doesn't outright say it, Hiccup's clearly disappointed in Astrid for keeping secrets about Heather from him.
- The Mole: Heather is feeding Astrid info on the Hunters.
- No Indoor Voice: When the riders enter the cave with 3 Snow Wraiths, Tuffnut wakes them up when he talks too loud.
- Poor Communication Kills: Heather is on the riders' side, but doesn't let Astrid tell anyone. It takes Hiccup nearly bringing Heather down for Astrid to finally tell them.
- The Reveal: Not only is Heather working with Astrid to spy on the Hunters, but apparently the Hunters have a scary and mysterious leader named Viggo Grimborn.
- Secret-Keeper: Astrid, on Heather's request, is keeping it secret from Hiccup that Heather's spying on the Hunters. Astrid isn't really comfortable doing it as she worries Heather could get hurt and she doesn't like lying to Hiccup.
- Suspiciously Specific Denial: Astrid claims that Heather and her dragon won't be a problem for the riders, but when asked why all she can come up with is that the Riders out number her.
- Tempting Fate: Quite a few this episode.
- A benign example, Hiccup loses Astrid in a snow storm and Snotlout claims she ditched him, which Hiccup annoyingly denies. Later it's revealed that yes she did purposely ditch him.
- Tuffnut does it three times, first he states it's a good thing there is only one Wraith— there are three; then he says it's a good thing they are asleep— one wakes up; finally he says it probably won't notice the riders— it notices them instantly.
