Tuffnut is eager to impress his visiting cousin, Gruffnut. But Ruffnut is suspicious of his real reasons for coming to Dragon's Edge.

The Dragon Riders attend Berk's 400th anniversary celebration, where a bounty on Hiccup's head casts a dark shadow over the festivities.

While trying to stabilize the volcano that threatens to destroy Dragon's Edge, the Riders discover troubling evidence of new Hunter activity.

The Riders accept an invite to Berserker Island, where their reunion with Heather, Dagur and a young familiar face is interrupted by a sudden revolt.

During a trip to Wingmaiden Island to find a Dragon Eye lens, Snotlout challenges Hiccup's leadership. On another island, an unlikely romance blooms.

While visiting Wingmaiden Island, a baby Razorwhip bonds with Ruffnut, who suddenly finds herself trying her hand at being a Wingmaiden.

The Riders race to the home of the true King of Dragons. But the Flyers are already there, and they soon come face to face with the legendary creature.