Christmas Bride (Hiatt Regency Classics #5)
Brenda Hiatt

Holly has always dreamed of adventure and heroics. In fact she would far rather travel to France to be a spy for the British like her twin brother, Noel, than make her London debut--until she meets the handsome Marquess of Vandover. After a whirlwind courtship and a Christmas Eve wedding, Holly's life seems full of promise. She is deeply in love, and her new husband's career in the Foreign Office allows her to rub shoulders with diplomats and ambassadors, feeding her love of adventure. Alas, her inept attempts to assist her husband in his diplomatic career--and become a heroine in her own right--tempt her to trust the wrong person. Suddenly Holly is plunged into a terrible conflict of loyalties, where she must choose between saving her nearly-broken marriage--and her beloved brother's life!