Spitelout has gone missing, and it's up to Stoick, Snotlout and Hiccup to find him, leading to a battle with a Singetail for control of a remote island storehouse.
Tropes:
- Bait-and-Switch Comparison: Snotlout, looking toward Stoick (riding his dragon, Skullcrusher) and the aggressive Singetail behind him:Snotlout: I don't know who's worse, that fire-breathing maniac, or his dragon!
- Brought to You by the Letter "S": Snotlout assumes the "S" Spitelout built on the Storehouse is for "Spitelout" (or "Snotlout"), but Spitelout claims it's for "Storehouse". Turns out it really was for "Spitelout".
- Call-Back:
- Stoick notes that being made a member of Astrid's Auxiliary Unit has gone to Spitelout's head.
- When an unbeatable dragon moved in after he built an empty storehouse, Spitelout refused to move on and find a better place, insisting on staying and fighting instead. Like Hiccup explained in the first film, "We're Vikings — we have stubbornness issues."
- Call-Forward: Hiccup notes that the Singetail looks familiar. He's most likely mistaking it for a Stormcutter (the species of Valka’s dragon Cloudjumper), which also has four wings.
- Everyone Has Standards:
- The twins love explosions, but Snotlout nearly burning down Hiccup's forge leads to them suddenly extinguishing the flames, followed by disapproving finger wags.
- While Hiccup may have let it slip that he thinks Spitelout is lying about finding the island first before the Singetails, he was shocked when Stoick accused Spitelout of deliberately hiding how the Singetail can emit fire from its belly, therefore setting up Hiccup to get hurt.
- Following from the above, Spitelout may be an arrogant jerk, but he wouldn't deliberately set up either Stoick or his son to get hurt by a Singetail.
- Freak Out: Snotlout goes into instant panic mode when Stoick reveals that Spitelout has been missing for a month.
- Freudian Slip: Hiccup tries to act as the Only Sane Man between his father and the Jorgensons, but he reveals his own skepticism of Spitelout's honesty when Snotlout asked if Hiccup is calling his father a liar. Hiccup reflexively said "yes" before catching himself.
- Generation Xerox: Stoick and Spitelout's relationship has many parallels to Hiccup and Snotlout's.
- Hidden Depths: Hiccup finds out that the reason why Snotlout and Spitelout are so competitive with him and his father, respectively, is because the Jorgensons deeply want the respective Haddocks' approval.
- Honor Before Reason: The only reason Spitelout has spent a month fighting the Singetail instead of giving up his choice of location for a storehouse.
- The Illegible: The only clue to Spitelout's whereabouts is a map in an "indecipherable code" that Snotlout recognizes as just simply being Spitelout's poor writing.
- Know When to Fold 'Em: Stoick realizes he should be more supportive of Spitelout and joins the battle to defend the storehouse. Despite this, once multiple Singetails appear, Spitelout accepts that they should just abandon the island and find a new place to build the storehouse.
- More Dakka: The Singetail can shoot fire from just about anywhere on its body.
- Only Sane Man: Hiccup as the peacemaker between his stubborn father and the prideful Jorgensons.
- Papa Wolf: Hiccup was nearly burned alive by the Singetail fire from its belly, which quietly angers Stoick, who thinks Spitelout deliberately left that fact out.
- Riddle for the Ages: It's never made clear as to why the Singetail was attacking the storehouse.
