The fourth book in the Libertus series, this follows the whole 'Libertus is unwillingly dragged into a mystery again'. After the third book, where he caught a glimpse of his lost wife, he's especially unwilling to investigate.
But, Libertus is accompanying the Roman Governer (of what was then Britain), so he has no choice but to investigate the death of Caius, the chief corn-officer - a pretty important guy in Roman times. Caius' mother is insistent that the murderers are his young wife and her lover, the charioteer Fortunas. But, his first wife and son still live in the same household, and they all have a pretty strong motive for murder. When Libertus gets beaten up and another body is found, it's clear that there's more to this case than what everyone first thought.
As always, there's a twist in this story that I did not see coming. In fact, I have yet to find a story in this series where I could predict the murderer. I guess I'm losing my touch. I had to re-read the ending of the book a few times before I even saw all the clues.
The characterisation here doesn't move forward very much. Most of the book is wrapped up in the mystery. The only surprise came at the end, because Libertus' search for his wife made a huge huge jump. I'm not saying anymore because that would be a spoiler, but suffice to say, if you're interested in this particular subplot, then this book is a key turning point. Extremely important turning point.
I'm still loving this series. I hope I can find a used copy one day and get the whole collection.