Sylvester, Duke of Salford, somewhat self-important and a bit of an arse, decides he needs a wife and clinically begins to consider suitable young ladies. Persuaded by his godmother that Phoebe Marlow (her granddaughter, might suffice he goes to Wiltshire to meet her, finding her overbearing parents insufferable and Phoebe a nondescript country miss. She's had one season in London and on returning home has (secretly) has written a novel in which Sylvester (whom she met only once) is the thinly disguised villain. It turns out that Phoebe, far from nondescript except when her stepmother is urging her to be on her best behaviour. She learns that Salford is likely to propose and decides to run away to London, to her grandmother, to avoid being married to an insufferably arrogant man she barely knows. Persuading her best friend (male) to drive her she gets herself into an awkward situation which Sylvester gets her out of. This follows Heyer's usual pattern of misunderstandings (especially when the novel is published and becomes the talk of the ton) and an eventual reconciliation, so we get the expected ending, of course. (And Sylvester is not quite such an arse by the end of it.)