The Rake and the Heiress by Marguerite Kaye

He will help her at a price no lady should be willing to pay! Any virtuous society lady would know to run a mile from Mr Nicholas Lytton. But Lady Serena Stamppe, returning from exile in France, is blissfully unaware of this rakehells reputation. In any case, he just happens to be the one person who can help unlock the mystery surrounding her inheritance. Accepting Nicholass offer of assistance, Serena soon discovers the forbidden thrills of liaising with a libertine excitement, scandal and a most pleasurable seduction!