Beth Culpepper is a lady's maid who is mistaken for a lady! Cast off and stranded at an inn in the way to London, she doesn't feel strong enough to dispute it. The handsome Marquis of Wrexham mistakes her youthful appearance as that of a gently bred schoolgirl whom he feels impelled to help. How did a good girl, proud of her position as lady's maid to Miss Sophy Ludgate, come to this? Easily - for as Beth reflects: "To obey or not obey Miss Sophy was bound to lead to this. For Miss Sophy was a devil." The marquis's sister, Princess Emmeline (a widow of the ruler of a small European principality) further mistakes Beth's identity, believing her to be her former mistress, Sophy Ludgate. Having once seen her on a shocking trip to Vauxhall Gardens, Beth denies it, but accepts the escort of brother and sister to London, where she hopes to seek employment.
Wrexham, lured into more gentleness by assuming Beth to be younger than she is, finds himself shocked to be feeling quite so close to a young lady who soon tells him she is 19. Could this protective feeling she aroused in him be more? Once in London, there are reasons that the marquis and his sister will not release her, and she finds herself a guest in a great house - where she nevertheless finds the household in turmoil. Although terrified of being discovered, as a pretender, she finds herself poking her nose into matters that might not concern her. Her humour and goodness make a bond with her hosts, and this just increases her guilt. Meanwhile, Sophy Ludgate is making mischief elsewhere. What else can she do that threatens Beth? Will Beth be exposed? Will she manage to escape into the evil streets of London, where respectability seems like an unreachable goal for a maid who has no character from her mistress? And can she ever recover from her fatal attraction to a man so far above her that it is impossible to even consider it? Despite her panic, Beth tries to be of use to the marquis and the princess, feeling closer to them each day, while knowing that her day of judgement is coming soon...