This graphic novel takes place mere minutes after the end of How to Train Your Dragon 2.
Picking up just after the events in How to Train Your Dragon 2, Hiccup, Astrid, and company are called upon to assist the people of an earthquake-plagued island. But their lives are imperiled by a madman and an incredible new dragon who even Toothless—the alpha dragon—may not be able to control!
Starting right after the events of How to Train Your Dragon 2, the recovery of Berk has started. Whilst Hiccup is introducing Berk to the reader, Snotlout is just barely clinging onto a runaway armoured Thunderclaw. Hiccup eventually swoops in, with toothless and fixes the situation immediately. Gobber eventually catches up, to find the armoured Thunderclaw. Gobber was getting rid of the dragons armour form Drago's dragon army. It turns out this particular Thunderclaw knocked Drago's prosthetic arm off, and it gets to keep his armour. Whilst this is happening Eret, son of Eret has been knocked down by villagers calling him an outsider, saying they can't trust an outsider when another had destroyed their home. This eventually reaches a resolution, with Hiccup having to draw his Inferno sword out.
Up in the great hall, Hiccup, the new Chief of Berk, is finding it difficult getting the peoples approval of him. He still feels that he needs to gain their trust as Chief, but before he can dwell on that idea, Fishlegs comes in with news of a visitor.
People from an island of Nepenthe had come to Berk in search of help from Stoick. Calder had been sent to Berk by King Mikkel the Munificent. Shortly after a little explaining Hiccup and Calder are discussing Nepenthe situation. On their Island there has been constant earthquakes. Growing louder and more noticeable every time. Hiccup agrees to come and help, although Berk is having their own problems, appointing Astrid as acting Chief, in which gets quickly given to Gobber as Astrid is coming with Hiccup to stop him from getting into any kind of trouble.
- The tribe begins construction of Stoick's monument which ties to the end of How to Train Your Dragon 2.
- In this comic, we learn that Thunderclaws don't fly when they are panicked.
- This is the first appearence of the Foreverwing outside of video games.
- Hiccup Horrendous Haddock III
- Astrid Hofferson
- Gobber the Belch
- Fishlegs Ingerman
- Snotlout Jorgenson
- Tuffnut Thorston
- Ruffnut Thorston
- Eret, Son of Eret
- Drago Bludvist (mentioned only)
- Stoick the Vast (mentioned only)
- Night Fury
- Deadly Nadder
- Monstrous Nightmare
- Hideous Zippleback
- Submaripper (comics)
- Unknown Tidal Class Dragon
- Whispering Death (mentioned)
- Screaming Death (mentioned)