The Wicked Duke — Madeline Hunter

She appeals to his wicked inclinations, but he never expects she might snare his heart....

Suspected of his brother's murder, Lancelot Hemingford, Duke of Aylesbury, was forced to give up his hell-raising habits in London for the anonymity of quiet country living. So, when an opportunity arises to clear his name in exchange for proposing to the niece of a neighbor, he sees no choice but to accept. Plus, seducing the reluctant maiden will be a most intriguing challenge...

As Marianne Radley is dependent on her uncle, she must accept the Duke's marriage proposal at her family's request, despite her belief he is irredeemably wicked. But along with marrying him, she intends to sniff out the duke's unsavory secrets and expose them to the world: a plan that would be flawless were it not for one minor detail -- even she, with all her determination, is not immune to the charms of a rakish duke...