It starts off the absolute Regency-est, though. '"Do not, I beg of you, my lord, say more!" uttered Miss Milbourne, in imploring accents, slightly averting her lovely countenance, and clasping both hands at her bosom.' I mean, right? It only needs a harp.
And maybe a fainting couch. For fainting.
Ok so the Viscount of Sherrysomething offers his hand to Miss Melbourne, the Incomparable Beauty, and is turned down, so in a fit of pique he marries a penniless, motherless teenager he's known from childhood (and also because he can't have his inheritance until he turns 25 or marries, and he's only 23, for heaven's sake). She has been raised (and badly) by her cousin and the cousin's ugly daughters, and so knows nothing of society. Jinx ensue, of the highest order.
Because the viscount is something of a rake, and too young to realize that he has to change his habits upon marriage, so he's always teaching his wife card games and introducing her to low characters and teaching her inappropriate slang and then being baffled beyond measure when she thinks it's socially acceptable to gamble all her pin money away.
She better did, though.
Anyway, the orphan keeps getting into worse and worse scrapes until the viscount realizes he'll have to send her to his mother to be taught Ladylikeness, only the mother hates the orphan, so the orphan runs away. The viscount's friends are all of the opinion that the viscount should appreciate his orphan more than he does, so they hide the orphan while the viscount comes to realize that he loves her after all.
All is about to be put to rights when, what ho, an upset. The wrong masked man abducts a lady, a wallet is stolen, horses are ridden into a lather, and someone is stabbed (non-fatally. These aren't that sort of books).
And it's a fun ride, but it lacks the banter and humor found in LITERALLY every other Heyer I have read. Also, the viscount boxes the orphan's ears a few times and it's not even a thing. I KNOW, period piece, but it still gets my ick on.
BeHAVE yourself, tractor-wife.
On the whole, though, it is an easy and pleasant read. Seven caterpillars.