Rider Sandman, late Captain of the 52nd Regiment, hero of Waterloo, and also of this book, does not appear in the Prologue. That is a vivid, almost too vivid, description of a hanging at Newgate. The repulsive hangman, the victims, one of them a girl accused of stealing a necklace from her mistress, crying and protesting her innocence till the awful end (rightly, it turns out - the necklace is later found behind a sofa - too late, but nobody seems to care). (Sorry about that "spoiler", but you just know she is innocent anyway.)
Then we meet Captain Sandman, also a cricketing hero (yes, really!) but penniless because his father seems to have lost everything, money, title and all, and then died, and Sandman had to sell his commission to provide his mother and sister with money to live on. Now he is staying at the cheapest lodgings he can find, sharing it with thieves and prostitutes such as the irrepressible Sally. The contrast between his very correct attitude and her very improper approach to life is perfect, while the difference between her cockney thieves' slang (the "flash" language) and his very posh English is frequently laugh-out-loud amusing.
But there is not only Sally, the whore and would-be actress, there is Rider Sandman's one true love, Sir Henry Forrest's daughter Eleanor, for whom her mother (for obvious reasons) no longer considers him good enough. And there is the Countess of Avebury, an ex-dancer who managed to marry one of her admirers, but is murdered while having her portrait painted.
The artist is duly tried, convicted and condemned. But then Sandman is recruited to investigate the case becasue someone in high places has petitioned on the artist's behalf. Sandman is at first unenthusiastic, believing the artist, Charles Corday, to be guilty of rape and murder. Then he goes to Newgate and meets him, and changes his mind – and has only days to find the true murderer.
Many books are described as page-turners. This is a real page-turner. I loved it, and love that immediate post-Napoleonic-Wars period - Cornwell proving himself as good at poverty and sleaze – at life in 19th-century London as it really was - as he is at life among the battling Saxons and Danes who lived in that same England one thousand years earlier.