After four years traveling on the continent, Madeline de Lacy, the duchess of Magnus, is lost by her father in a card game to Mr. Remington Knight. She resolves to go to London and explain why it’s ridiculous for them to be wed, but she’s sidetracked and persuades her cousin and companion, timid Miss Eleanor de Lacy, to switch places with her and to go on to London to hold off the vengeful Mr. Knight. Eleanor agrees. Madeline offers Eleanor one piece of advice - to be bold and act as Madeline would in like circumstances. In Remington’s expensive townhouse, Eleanor discovers he is handsome, diabolical, and determined to wed her, the woman he believes is the duchess. Remington’s concentrated courtship amazes her. For all that he thinks he has won her hand in marriage, he seems attracted and determined to seduce her. Worse, she’s drawn to him. He’s the kind of man she should despise: ruthless, vengeful, willing to use his great wealth to buy his way into society - and worse, after meeting him, she has no faith that the real duchess will be able to talk her way out of a marriage with him. Yet there’s something about him that touches Eleanor’s soft heart. He seems like the loneliest man she’s ever met, and in the dark of the night, she imagines how she could comfort him. To her shame, Eleanor lusts after her cousin’s fiancé. He accepts invitations to the most glittering events of the London season, introducing Eleanor as the duchess, and because Eleanor and Madeline share a marked resemblance and were gone for so long, only a few remark on the changes the years have wrought. But shy Eleanor is mortified by the attention of the ton. She makes mistakes: she pays attention to the wrong people, she forgets to enter a room first when protocol demands it. Worse, she rescues puppies, scolds dashing gentlemen for racing through the streets, and becomes known as the most eccentric, original lady of the season. She becomes, to her surprise, a success. Remington doesn’t know what to think of his duchess. He expected a haughty, rigid aristocrat. Instead he has acquired a modest, soft-hearted lady - a lady he could fall in love with, if only he wasn’t bent on revenge.