On a world settled by colonists from Earth, the Governor strikes a deal with seven shadowy figures, the Quell, to rid him of a nuisance colonist.

On the same stormy night, the Fourth Doctor and Romana pay a housecall on Lord Samuel, last of the Warren family. He tells them the story of his ancestors, many of whom have faced death at the hands of the Quell, only to be saved by Romana and the Doctor.