An unlikely ally helps Hiccup uncover Singetail behaviors that can be exploited to conquer the Flyers. An overconfident Krogan makes a strategy error.
The Riders flee to Berk, where Stoick's plan for defeating the Flyers, which will require a painful sacrifice, spurs Hiccup to seek an alternative.
After Stormfly tangles with two poisonous Slitherwings while defending Garff, Astrid must risk her own life to get an ingredient to make an antidote.
When Ruffnut refuses to become Throk's bride because it would mean leaving her twin, Tuffnut fakes his own death to give her the freedom to marry.
When Heather goes to meet a man claiming to have seen Oswald, she walks into a trap that forces the Dragon Riders to pay a dear and unexpected price.
A sketch in an old diary leads Hiccup and Fishlegs back to Vanaheim, where they help Dagur search for his long-missing father, Oswald the Agreeable.
Venezuelan president Nicolas Maduro makes moves toward turning the country from a democracy into a dictatorship, creating a growing opposition to his rule.
Jestro and the Cloud of Monstrox builds a new stone army from giant building blocks to crush Knighton. The Nexo Knights try to convince Rockowski, a demolition expert, to help them.
In 1997, a son must teach his mother how to use the Internet over the phone after leaving behind an important document on his laptop.
Bob mistakes a mud-covered pig for Rolly and accidentally leaves him behind on a farm.
Elena and her friends get stranded on a sailboat and are rescued by a mysterious ship.
Tick and Arthur have a run-in with local villainess Miss Lint and her gang, who will stop at nothing to get back the mysterious supersuit that Tick took from them and gave to Arthur. Dot, Arthur's paramedic sister, moonlights for an unsavory business.
Tick and Dot help Arthur try to control his flyaway supersuit as the Pyramid Gang pursues them. Miss Lint has an unexpected caller.
Tick and Arthur try to use Ramses to prove that the Terror is alive and run into trouble. Miss Lint takes the advice of an old friend.
Arthur takes a break from hunting the Terror and tries to get back to his safe, normal, and unheroic life as an accountant unaware he's being stalked by the menacing vigilante Overkill. Tick confesses to an existential crisis.
Tick crashes an Everest family party to convince Arthur's sister Dot of her brother's super-heroic destiny. Another more dangerous party-crasher arrives to threaten Arthur and his family.