Katharine is a beautiful but penniless woman who has spent most of her life at a school in the country, educated to be a governess. One day, her uncle comes and carries her off to London, promising her a better life. Unknown to Katharine, her uncle has a hidden motive.
In London, she attracts several admirers, including two brothers: one a gamester who works at her uncle's gaming house; the other an ex-soldier, nicer than his brother but still something of an adventurer. She also meets Judith, an old friend, now married.
As she slowly realizes there is a price for her new life, she also finds it's one she can't bring herself to pay. Unfortunately, her uncle has no intention of letting her off the hook: He has debts, and intends Katharine for the first wealthy man who will pay them.
Katharine is a bit exasperating, because she can't seem to grasp that every time she rejects one scheme, her uncle resorts to the next option, which is always worse. She is honest to a fault, and inevitably paints herself into a corner, where the only option is to fall in with the gambler brother's plan to trick an elderly lady.
And what of the hero, the ex-soldier? He eventually comes to her rescue, of course, but shows an equally exasperating tendency to keep "testing" her honesty. This seems a bit overbearing, since he has good reason to know she is simply in over her head--and it's partly due to him that Katharine feels she has no option but to run off with his brother.