To sin with a scoundrel - Cara Elliott

A reclusive widow known for her scientific scholarship, Lady Ciara Sheffield is shadowed by rumors that she poisoned her husband . . .
A rakehell rogue notorious for his devil-may-care antics, Lucas Bingham--the Earl of Hadley--is not accused of murdering anything--save for the rules of Polite Society. The only thing they have in common is seeing their names featured in the lurid gossip columns of London's newspapers. Until an ancient manuscript draws them together.

Ciara needs a titled fianc to quell the slanderous speculations which may send her to the gallows. Lucas needs brilliant scholar to help his elderly uncle decipher the secrets of the mysterious manuscript. So when her friends urge her to accept the earl's proposal of a temporary alliance, Ciara decides that she has no choice but to make a deal with the Devil.
And so begins a seductive dance of sinful pleasures and hidden desires as the two of them waltz through the mansions of Mayfair. Lies, intrigue, treachery, sex. They find themselves facing slanderous whispers, unscrupulous relatives-not to speak of their own simmering passions, which quickly ignite into dangerous flames. It's a potent mix and the result may be explosive-and perhaps deadly-if they don't watch their step.