The Blackguard’s Beauty by Tabetha Waite

Fleur Davies would do anything to protect the last of her family—her twin brother, Flavian. From fighting a duel in secret, to daring to put her virtue up for auction with the intent to clear a gambling debt, she told herself she was prepared to do whatever was necessary to ensure their survival. However, when she finds herself at the mercy of an intimidating man like Mr. Porter, it isn’t fear that courses through her. There is something about those glittering silver eyes that she can’t quite ignore…
Drake has lived a life that would make most people cringe. He had been called the Devil with due cause. He never hesitates when it comes to getting what he wants. His past is littered with criminal activity, but he decides to put all that behind him. When he encounters Fleur and her errant brother, he is intrigued. But when she sends him on a merry chase, he finds that he is inexplicably drawn to the raven-haired beauty. For the first time in his life, Drake wants more than revenge.
When they suddenly find themselves at the mercy of the London underground, Drake and Fleur have to become unlikely allies to save her brother’s life. But will this fiery attraction be the end of them all?