The beautiful old pre-Elizabethan house and estate of Whiteladies is strictly entailed. The two ladies in their late fifties who live there, Susan and Augustine Austin, are the daughters of the prior possessor.
Augustine, who lives and dresses as a penitent nun, believes Whiteladies is cursed. The ladies have partially raised the current possessor, Herbert, and his sister Reine. But now he is dying in Switzerland; and once he dies the sisters must leave the only home they have ever had. The estate will go to the presumptive heir-at-law Mr Farrel-Austin (a man they deeply dislike), unless the missing branch of the family can be found, having the true heir-at-law.
Susan manages to discover the missing branch of the family in Belgium. The true heir M. Austin is an old man, and his wife Madame Austin is anxious for their expected grandchild to be next in line. The problem is that the entail passes from male to male, whereas the expected grandchild will be the child of the Austins' daughter, not of their deceased son's wife. Madame Austin and Susan decide between themselves to pass this child off as the next heir, if the expected child is a boy. (Susan rationalizes to herself that it will be a justice of sorts to have the succession pass through the female line - but this does not keep her from experiencing tremendous guilt over tampering with the succession.)
The child is indeed a boy; but many other things do not go as planned; and Susan finds herself trapped by her own deception.
This novel has several story lines, including some centering on the younger generation - Herbert, Reine, and their cousin Everard.