Mr Zero - Patricia Wentworth

Gay Harkwicke has had her fill of her giddy cousin's predicaments. But when Lady Sylvia Colesborough cries blackmail, Gay listens twice. A mysterious Mr Zero has asked Sylvia to steal important government papers from her prestigious husband, Sir Francis, and from the Home Secretary. Otherwise, he will reveal her huge gambling debts. Gay begs Sylvia to confess to Sir Francis. But she refuses and the die is cast. Hoping to scare Mr Zero off, Gay and her fiance, Algy, rush to the scene of the saboteur's rendezvous. But by the time they arrive, murder will be done, as well as espionage. And Algy, assistant to the Home Secretary, will be the prime suspect. Somehow Gay must foil the murderous Zero...or lose the man she loves.