Her first novel was "The Dark Shore" (1965). She published several other "gothic" novels before she turned to the first of her family sagas, "Penmarric" (1971), which details the fortunes and disputes of the Penmar family in Cornwall during the nineteenth and twentieth centuries. An important theme of the story is how the mansion of Penmarric becomes controlled by various branches of the family. The family fortune was made in the Cornish tin mining industry, which is discussed throughout each one of the six parts, each with a different character as narrator. As is made clear by the chapter headings, the fortunes of the family closely parallel the Plantagenet family, including Henry II of England and Eleanor of Aquitaine, with the mansion representing the throne. It was adapted into a television series with the same name in 1979.