A Wicked Lady — Anne Herries

Masquerading as a French Comtesse, Margaret Hazelmere quickly becomes the target of Lord Giles Benedict. Giles detects the Comtesse is hiding something and, suspecting she's a French assassin, he determines to investigate her.... But as they fall in love, danger comes ever closer. And although Giles would give his life for Margaret's -- will she still love him when she discovers the truth....?