The TARDIS arrives on Fang Rock, a small island off the English coast, around the start of the 20th Century. The Doctor and Leela seek shelter at a lighthouse where the island’s only inhabitants - Ben, Vince and Reuben - operate the recently-installed electric lamp to warn ships off the treacherous rocks. A passing ship crashes on the rocks as a freak fog bank descends, and the survivors - Colonel Skinsale, Lord Palmerdale, Adelaide Lesage and Harker - stumble into the lighthouse. There they find themselves prey to a Rutan - one of the race engaged in a perennial war with the Sontarans - whose spaceship has crashed in the sea.