Olivia and the Masked Duke by Grace Callaway

He saved her life when she was a girl. Now she is a woman determined to heal his heart…
Spirited debutante Lady Olivia McLeod, cherished daughter of the Duke and Duchess of Strathaven, has two interests: solving mysteries and winning the love of her rescuer and secret crush, the infamous Duke of Hadleigh. When Livy joins Lady Charlotte Fayne’s charity for young ladies and discovers that it is a front for a covert investigative agency, she is thrilled. Livy dedicates herself to solving a deadly case; little does she realize that the path to danger will also lead to her heart’s deepest desire.

Notorious widower Ben Wodehouse, the Duke of Hadleigh, has only one goal in mind: redemption. After his tortured past, he channels his demons toward helping others, and the last thing he wants or deserves is innocence. Yet temptation taunts him by transforming the little girl he once saved into an alluring young woman. A dozen years younger than him and the daughter of his friend, Livy is everything he cannot have…and everything he needs.

Will perilous secrets, past and present, tear Livy and Ben apart? Will succumbing to their forbidden desires lead to their happily ever after? Find out in this steamy, slow burn, friends-to-lovers romance filled with mystery and adventure!