A chance encounter on a train platform leads a bored teacher to assume the identity of a socialite, setting off a precarious deception. Anne Lessways, seeking an escape from the monotony of her teaching career, agrees to impersonate Lady Gillian Haymer for one week. She enters the social sphere of Wynchcombe, navigating the expectations of a family party while maintaining the ruse. The narrative follows her attempt to sustain this false persona until the arrival of Gillian's ex-husband threatens to expose the truth.

Readers often note the lighthearted yet suspenseful nature of this classic identity-swap narrative. Discussion frequently centers on the moral implications of Anne's decision and the tension generated by the arrival of the ex-husband. Critics highlight the author's ability to maintain a consistent pace throughout the week-long ruse. The book is recognized for its focus on character dynamics within a confined social setting. Many readers appreciate the straightforward prose style that characterizes the author's body of work.