Frances Hadley has had it. After years of running her brother's estate, she overhears her money-grubbing aunt conspiring with a perfectly odious man to sell her off to him in marriage. So she decides that she'll escape to London and her wayward brother to demand control of her dowry herself. She cannot travel to London alone as a woman but she can do it disguised as a boy and so she cuts her hair, dons pants, and takes off, only to be stopped by bad weather at a small inn. Obviously young and innocent, she is given the last available room, one usually kept for members of the Valentine family. Since it is the night of the annual Valentine Ball, hosted by Venus, the Duchess of Love, no one expects a member of the family, always present for a command performance at this matchmaking ball, to need shelter. And yet, Jack Valentine, the duchess's third son, unexpectedly shows up, running away from determined debutantes looking at him with an eye to marriage. When he sees the sleeping Frances, assuming that she's a lad, he decides that he can't kick the stripling out of the room and just shares the bed.
The next morning, with Frances still in the guise of a young man heading for his brother's home in London, Jack and Frances breakfast before leaving the inn where they meet an acquaintance who might have recognized Frances as the young woman she is. But it is only on the long journey to London that the truth about Frances' sex is revealed to a very angry Jack. When her brother is no longer at the address Frances knows, Jack takes her to his home and calls in his parents, the calm Duke and Duchess of Love, to help mitigate any scandal surrounding Jack and Frances' journey. Frances is unladylike, pushy, and temperamental. She's annoyed by her inability to run her own life outside of society's dictates. Jack, meanwhile, embraces his reputation as an incorrigible rake in order to hide the fact that he funds a home for downtrodden women, children, and prostitutes to try and help them out of their horrible existence in London's poorest areas.
As the Valentine family helps Frances reconnect with her own long estranged family on the maternal side, she and Jack come to appreciate each other and the ways in which neither of them conform to what society expects of them. But in amongst all of this getting to know each other and reconnecting with family, Jack is also trying to uncover the identity of a serial killer loose in London, one who is similar to Jack the Ripper in that he targets prostitutes and those society ladies whom he has deemed immoral. And it gets personal when the rumors about Jack and Frances at the small inn come to light and Frances herself is put in danger.
Frances is an unconventional, feisty heroine and Jack is rather a paragon as a hero but they are appealing enough. The climax is not unexpected and the happily ever after is delivered just as required, making this is good book for an afternoon. However, there are some unbelievable bits given the time setting of the book. That Jack's family would immediately enfold Frances into their hearts and successfully head off the scandalous situation is pretty unlikely. There isn't a lot of dramatic tension between Jack and Frances as a couple and so the plot device of the serial killer is necessary to given the story some legs. While this may not stay with the reader long past the last page, it is a quick and enjoyable read for fans of the historical romance genre.