The year is 542. While plague stalks Constantinople, an angel sets John the Eunuch on the trail of a human killer.

Peter, John's elderly servant, claims a heavenly visitor revealed a murder to him. It transpires Peter's old army friend has indeed been stabbed, but then John discovers that Gregory was not what he appeared to be.

Is the solution to the mystery to be found in a hidden identity, in the will made by a dying ship owner with a wayward son, or perhaps even amid the oracles in the merchant's garden?

John's quest leads him to churchmen and whores, lawyers and bear trainers. Suspects include a dealer in dubious antiquities, a resourceful bookseller, a court poet fixated on bereavement, and a holy fool who outrages the city by dancing with the dead and invading the empress' private bath.

Only a man of unbending principle could hope to find justice in a terrified city where the good and the bad are struck down indiscriminately, where disorder rules, and where witnesses may die before they can be questioned. A city, in short, where death is the murderer's accomplice.