With the Midnight Sun in the skies, Berk and its riders go without sleep and suffer insomnia. On the way back to the Dragon's Edge, Hiccup and Toothless become prey to a group of new dragons.
Tropes:
- Artistic License – Biology: The twins claim that their Uncle Gorstag had insomnia for 27 years straight. In reality, modern experiments have claimed that the average time humans can go without sleep falls somewhere between 11 days to a few months and even (when under Fatal Familial Insomnia) 2 years before suffering from severe mental and physical degradation and perishing.
- Cycle of Revenge: Discussed by Stoick and Hiccup, because Hiccup is now impatient enough to want revenge on Viggo. While Stoick agrees that revenge feels nice in the short term, he has experience in cyclic vengeance and doesn't want Hiccup to go through that.
- Endless Daytime: The Midnight Sun is an annual two-week long astronomical event where the sun does not set.
- Genius Ditz: The twins are the ones who explain the symptoms of insomnia, with bigger words than you'd expect from them. They're even keeping a log.
- Go-to-Sleep Ending: The episode ends with Hiccup and Toothless catching up on their sleep once they return to the Edge.
- Insomnia Episode: The perpetual daytime is driving the Vikings bonkers to varying degrees from a lack of sleep.
- The Insomniac: Everyone suffers from this due to the lack of sleep via the Midnight Sun, each suffering from a different symptom which gets worse as the episode goes on.
- Hiccup becomes careless with a slower reaction time.
- Astrid is overcome with euphoria, becoming obnoxiously optimistic and dangerously carefree.
- Snotlout suffers from severe mood swings, switching from laughing to crying to shouting in an instant.
- Fishlegs becomes increasingly paranoid of the others.
- Heather loses all sense of coordination, tripping on her own feet and spilling her water bucket trying to clean Windshear. She later starts losing focus, confusing Windshear with a rock.
- Ruffnut and Tuffnut are overcome by visual and auditory hallucinations.
- Gothi spends her time "babbling" for hours, drawing in the sand with a blank stare.
- Sven dances with his sheep, though Hiccup points out that he does that all the time. Gobber agrees that it's a bad example.
- The Magnificent: Hiccup claims that Stoick was going to be called "Stoick the Vindictive" before "Stoick the Vast" stuck.
- Shout-Out: Once they take to the air, the Shadow Wings start behaving like biplanes and bombers, resulting in several scenes reminiscent of Great War dogfighting movies. The gigantic Shadow Wing itself strongly resembles a gigantic warplane, with smaller dragons as "guns" shooting flak.
- Stating the Simple Solution: Although since they can't talk, the dragons just do it; having enough of everyone's insomniac behavior, they simply gather everyone up into a dark storeroom so they can take a nap.
- The Straight Man: The dragons collectively act like this to their riders, watching their insomnia-based behavior with confusion and bewilderment before they lock them in a basement to sleep it off.
- Wounded Gazelle Gambit: The Shadow Wings use this to lure in the Dragon Hunters and later Hiccup and Toothless.
- Wrong Genre Savvy: Hiccup assumes the Shadow Wings need help, even after seeing the state of the dragon hunters' camp and falling for their Wounded Gazelle Gambit. They're actually just trying to eat him and Toothless, which he only realizes after he sees the biggest one.
