This new episode in the Cato/Macro series is the best so far. The two are in charge of auxiliaries in Syria, under the command of the Longinus (who hates them). They get involved in the affairs of Palmyra, a kingdom between Roman Syria and Parthia. There's a lot of action, and some good twists and turns as things escalate.
I also liked that Cato and Macro are back (almost) to their natural place. The last book (or two, maybe) in which they are required to act as spies primarily felt a bit less punchy.