Although you would think the spy genre would be jaded by now, this story is a refreshing and enchanting love story. Okay suspension of reality is required as people don't just appear in supposed english high society and get accepted.
Anyway the heroine of the story is a young lady in disguise "Kit" who has been masquerading as a boy for most of her 19 years. She comes to London to supposedly ferret out whomever is stopping the shipment of contraband goods to the french (on behalf of her father).
Once in London, she manages to get herself accepted into the Earl of Evenden "Alex's" household supposedly as a debt owing to Kit's father from the previous Earl (slightly incredulous but suspension of implausible required). She takes on the role as his male cousin. Note that Alex does find out very early on in the book that Kit is female in disguise.
Without being overtly sexual, its little scene stealers which make this a sensual story worth reading. For example: where Kit is standing in the park (in her disguise as a boy) and is confronted by her cousin Alex on horseback and he lifts her up behind him on his horse and she shifts closer to him to smell his scent and puts here arm around his firm flat stomach to suport herself. Or where Kit is being fitted out for a suit and is being measured by a tailor, whilst Alex plays chaperone and looks on....its the power of the mind which provides the erotica.
Also little gems like naming the horses in the story from Romeo and Juliet ie Tybalt, Mercutio and Benvolio....priceless
Anyway I could read this one over and over and would definitely recommend a purchase.