In the near future, "The Running Man" is the top-rated show on television, a deadly competition where contestants must survive 30 days while being hunted by professional assassins. Desperate for money to save his sick daughter, Ben Richards is convinced by the show's ruthless producer to enter the game as a last resort.

On the rugged isle of Berk, a Viking boy named Hiccup defies centuries of tradition by befriending a dragon named Toothless. However, when an ancient threat emerges that endangers both species, Hiccup's friendship with Toothless becomes..