The last person Sebastian Earl Carlisle, needs interfering in his life is Miranda Hodgkins, the flighty, free-spirited niece of his Lincolnshire neighbor and local orphanage manageress whom he and his siblings consider little more than a sister. A serious man with solemn obligations, Sebastian has planned to find a wife of rank who will preserve the solid reputation of his family. But he never planned on finding a beautiful, masked woman draped temptingly across his bed, begging to be seduced...and very nearly succeeding until he discovers that his seductress is none other than Miranda, who has mistakenly sneaked into the wrong bedroom.

In love with Robert Carlisle, Miranda planned a night designed to make Robert fall in love with her, only for it to all go horribly wrong when the man behind the mask reveals himself to be Sebastian. Mortified, she swears him to secrecy. But when Sebastian realizes that Miranda is in London for the season, he fears the worst-that not only will Miranda make a fool of herself over Robert but that her antics will cost him his proper wife. The two strike an agreement: he'll help in her pursuit of Robert if she promises to behave.

As Sebastian helps Miranda seduce Robert the unthinkable happens: he begins to have feelings for her. The last thing he needs is to tie his respectable title to a woman as reckless as Miranda. Will he sacrifice his heart to give his estate the proper countess it needs? Or will sensible, practical Sebastian final let himself fall, damn the consequences?