In 1940 England, Mayfair society debutante Osla Kendall and brassy, determined typist Mab Churt, from London's East End, seem to have nothing in common—until they become roommates and colleagues decoding German messages at the top-secret cryptanalysis center at Bletchley Park. Elizabeth Finch, their landlady's shy, silent, bullied daughter, is an even less likely companion, but she possesses an unnatural talent for puzzles and soon is poring over code with an intensity that makes the rest of the world fall away. The stress of the work at Bletchley is relieved by Mad Hatter tea parties and high jinks, but eventually these give way to bitterness and betrayal, as the war exacts its cost on each of the women, leaving them scarred and alone. It is not until several years after the war and Bletchley's disbandment that the discovery of a possible turncoat forces the three women into an uneasy alliance and a frantic race to catch the traitor before it is too late. VERDICT Quinn (The Huntress; The Alice Network) writes with an immediacy and level of detail that keeps readers on the edge of their seats. Her latest is a deft blend of romance, mystery, and suspense that will appeal to lovers of those genres, and to her many fans.—Cynthia Johnson, formerly with Cary Memorial Lib., Lexington, MA

Quinn (The Huntress) returns to WWII and the secretive world of Bletchley Park in this immersive saga. Debutant Osla Kendall meets fellow Bletchley Park recruit and London East End resident Mab Churt on the train in 1940. While working at Bletchley, they share a room at the home of Beth Finch, a young woman beaten down by her demanding mother. After discovering Beth's talent for solving crosswords, Osla helps Beth get a job interview at Bletchley Park. Though Beth is shy and reclusive, she shines in her work on breaking codes. But when she discovers someone at Bletchley is likely a traitor, no one believes her. Soon, she she winds up the suspected traitor and is committed at Clockwell Sanitarium after having a mental breakdown. In 1947, almost four years later, Beth contacts Osla and Mab, who help Beth escape from Clockwell. Together, the women work to crack a code that will help them find the traitor. Quinn's page-turning narrative is enhanced by her richly drawn characters, who unite under the common purpose of Britain's war effort, and by the fascinating code-breaking techniques, which come alive via Quinn's extensive historical detail. This does not disappoint. Agent: Kevan Lyon, Marsal Lyon Literary. (Mar.)