Daring and the Duke by Sarah MacLean

Grace Condry has spent a lifetime running from her past. Betrayed as a child by her only love and raised on the streets, she now hides in plain sight as queen of London’s darkest corners. Grace has a sharp mind and a powerful right hook and has never met an enemy she could not best, until the man she once loved returns. Single-minded and ruthless, Ewan, Duke of Marwick, has spent a decade searching for the woman he never stopped loving. A long-ago gamble may have lost her forever, but Ewan will go to any lengths to win Grace back… and make her his duchess… Read more.