Dancing On the Wind: Fallen Angels #2:

Like his nickname, Lucifer, Lord Strathmore is know for unearthly beauty and diabolical cleverness. A tragic past has driven Lucien to use his formidable talents to protect his country from hidden enemies. It's a job he does superbly well—until he meets a mysterious woman whose skill at deception is the equal of his own. By turns glamorous and subdued, his enchanting adversary baffles his mind even as she dazzles his senses. A perilous mission has forced Kit Travers into a deadly gave of shifting identities and needful lies, where a single misstep might cost Kit her life. But her disguises are easily penetrated by the Earl of Strathmore, who may be a vital ally—or a lethal enemy. Unwilling to trust, yet unable to part, Kit and Lucien join forces to search the dangerous underside of London society. Yet even two master deceivers cannot escape passion's sensual web—or from an impossible love more precious than life itself. Book 1: Book 2: Book 3: Book 4: Book 5: Book 6: Book 7: