Watson's debut, Before I Go To Sleep, has sold a half million copies in hardcover, paperback, and ebook combined in 42 territories since its 2011 publication and won the Crime Writers Association Award for Best Debut Novel. Here, when Julie discovers that her murdered sister had been living a second life in a dangerous corner of cyberspace, she hunts there for clues to the killer. Instead, she finds a sexual playground that gives her fantasies free rein, which maybe isn't so smart. With a 350,000-copy first printing.

Sisters Kate and Julia are so close that Julia adopted her baby sister's son Connor, after Kate gave birth at age 16. Kate's brutal murder leads Julia to uncover the shady acquaintances she never suspected her sister kept and a darkly erotic secret life she finds irresistible even as it starts to destroy her family's ability to trust her. VERDICT Watson's second thriller (after the best-selling Before I Go To Sleep) offers an exciting mix of sex, murder, and mystery to please adrenaline junkies. [See review on p. 78.—Ed.]

Julia Wilding, the narrator of bestseller Watson's overstuffed second novel (after 2011's Before I Go to Sleep), lives a comfortable middle-class life in London with her husband, Hugh, a cardiac surgeon, and their adopted son, 13-year-old Connor. In Julia's younger and wilder days—she's a recovering alcoholic—she was an art photographer, but now she's content to take family portraits. Then tragedy strikes. Julia's younger sister, Kate, is murdered in Paris, and she throws herself into catching Kate's killer. Though the sisters used to be close, a difficult childhood and Kate's often unpredictable ways came between them, but not before Julia and Hugh stepped in to care for Kate's son—Connor is actually their nephew. Julia's quest for answers leads her to a sleazy online dating website, where she initially masquerades as Kate and meets a mysterious man, Lukas, who may or may not have known her sister. Soon she's embroiled with Lukas, as well as with Kate's roommate, Anna, both of whom have the requisite secrets, which are unspooled at a glacial pace. Agent: Clare Conville, Conville & Walsh Literary Agency (U.K.). (June)