Not Quite A Duchess — Alyssa Alexander

London 1794 Tess Murray, once a maid in a fashionable London townhouse, traded her apron for a pair of breeches to become a spy—a decision that cost her the man she loved. Determined to become a spymaster and command her own team, Tess is hunting a traitor smuggling muskets to France. Sebastian Moore, Duke of Northfield, spent ten years fighting to save his family's reputation. When he finds Tess in his warehouse—and muskets hidden among the goods ready to be shipped—he realizes everything he has worked for is at stake. He might be a suspect, and she might be a spy, but passion has no rules.