1938. Gillian Larkin is used to going unnoticed, until she is sent away to school and befriended by her roommate, the vibrant and spirited Violet Claybourne. As the Christmas holidays approach, Gilly can't believe her luck when Violet invites her to spend them at her home, the crumbling Thornleigh Hall.

At Thornleigh, Gilly is dazzled by the family's faded grandeur, and above all by Violet's beguiling older sisters who seem to accept her as one of their own. But following a terrible accident in the house's grounds, Gilly begins to realise the Claybourne sisters aren't quite what she thought they were. And if she's to survive in their world, she may have to become just like them . . .

A captivating novel of family secrets, desperate ambition and deepest betrayal, set against the winter of 1938, The Undoing of Violet Claybourne is the irresistible new mystery from the acclaimed author of One Puzzling Afternoon.