If there is one thing Marcus Corvinus hates more than doing the household accounts, it is politics. So when he is interrupted in the former to get involved in the latter, he is not best pleased. His brief is to conduct an unofficial investigation into an attack on the Parthian Prince Phraates, a task that taxes his (none too) diplomatic skills to the utmost. The attack is then followed by a successful murder of one of the Parthian delegation and a full diplomatic incident threatens. The byzantine twists and turns of the case give Corvinus a headache worse than his customary hangover, and it takes a violent threat to Perilla before he begins to get a grip on what is involved. Along the way he learns a lot about the spice trade - and has some problems with a basket of lampreys.