Lonely single mom Louise kisses a man at a bar, but when she arrives at work on Monday and meets her new boss, David, she is stunned to discover that he is the man she kissed. And then Louise bumps into Adele, who's new in town and in need of a friend, but she also just happens to be married to David. As Louise is drawn into David and Adele's orbit, she uncovers more puzzling questions than answers. The only thing that is crystal clear is that something in this marriage is very, very wrong. But in this taut psychological tale—the source of the 2021 Netflix series—Louise can't guess how far a person might go to protect their marriage's secrets.

"The strongest, most unsettling thriller of the year, with a final twist destined to provoke arguments for years to come. Read it now before someone spoils the ending for you."—John Connolly