When architect-turned-recluse Bernadette Fox goes missing prior to a family trip to Antarctica, her 15-year-old daughter Bee goes on a quest with Bernadette’s husband to find her.

As Hiccup fulfills his dream of creating a peaceful dragon utopia, Toothless’ discovery of an untamed, elusive mate draws the Night Fury away. When danger mounts at home and Hiccup’s…