The Adventuress (Lady Emily, #10)

Emily and husband Colin have come to the French Riviera for what should be a joyous occasion - the engagement party of her lifelong friend Jeremy, Duke of Bainbridge, and Amity Wells, an American heiress. But the merrymaking is cut short with the shocking death of one of the party in an apparent suicide. Not convinced by the coroner's verdict, Emily must employ all of her investigative skills to discover the truth and avert another tragedy.