Set after the events of How to Train Your Dragon 2, Berk is rebuilding in the fragile peace following the defeat of Drago Bludvist. As Hiccup Horrendous Haddock III quietly steps into the role of leader, burdened by grief and expectation, an unexpected arrival unsettles the balance: Eret’s estranged sister, a sharp-minded strategist who became the reluctant leader of her own village in his absence.