The TARDIS takes the Doctor and Martha to the Lake District in 1909, where a small village is being terrorized by a huge, scaly monster. The search is on for the elusive "Beast of Westmoreland"; Explorers, naturalists, and hunters from all over the country flock to the local mountains. King Edward VII himself heads to the search site, promising a knighthood to whoever finds the Beast. But there is something more sinister in the Lake District than the rampaging monster, and the Doctor soon finds himself part of the plan of an old terrible enemy. When the hunters themselves become the game, a desperate battle of wits begins, with the future of the world at stake.