Something Wicked by Jo Beverley

It was a night of danger and intrigue. Disguised as the mysterious beauty Lisette, Lady Elfled Malloren anticipates only fun and flirtation at the Vauxhall Gardens Masquerade. Instead, the dark walkways lead to an encounters with treason, a brush with death, and a night of riotous passion with her family’s most dangerous enemy — the elusive Fortitude Ware, Earl of Walgrave. His control is indisputable, his power unquestionable, his attraction undeniable. And after just one night, Elf knows she will never forget the man she should not love …