What a title! And the protagonist, Claudia, is not so different from the women surrounding Claudius himself (at least in the Robert Graves version) except that she was born and bred in the gutter while they were brought up in a palace.
Claudia is married to a wealthy wine-merchant. He is fat and middle-aged and yes, she is his third wife and she married him for his money, but, as she says, so what – he married her for her youth and beauty.
Nothing wrong with that.
What is wrong is that Claudia is a compulsive gambler and has run up enormous debts which she cannot pay and her husband must never know about. So she turns to a particularly lucrative form of prostitution – servicing senators who get a kick out of being beaten and humiliated by a beautiful dominatrix. However, four of her clients – then a fifth – turn up dead, and if the link between them – her! – should be discovered it would certainly be the end of her luxurious lifestyle and probably the end of her, literally.
So she sets out to catch the serial-killer of masochistic upper-crust Romans herself.