Charlotte Butterworth may be on her first London season, but she already knows she will never marry. Nothing interests her as much as numbers, and numbers seem to be of absolutely no interest to anyone else. And then there's...the secret.Callum Montgomery, Duke of Vernon, can marry the best. He's handsome and charming and perfect. In fact, he's been betrothed to the darling of the ton since he was seven, even if he does keep on putting off the wedding.When the roguish Duke of Vernon gains possession of some terrible, utterly shocking news about Charlotte, Charlotte needs to act quickly to keep the duke from revealing her secret.