The book is set in Rome and Ostia in AD90.[5]: xi The list of characters includes Marcus Didio Falco ("one-time hero; has he still got it?") and Helena Justina ("his wife, an absoluter heroine") from the Falco series, vigiles from seven cohorts, and members of five underworld gangs.[5]: xiii–xvii Davis has said that the plot involves a corpse dredged out of the Tiber, the "ever-warring gangster community", "the failings of the various public bodies who are supposed to tackle crime and threats to the community" and "a very elaborate joke about crime writing".[6]
The book refers to events from Davis's earlier book The Jupiter Myth.
The cover of the first UK hardback edition shows a barnacle-encrusted vase on a river-bed with blood flowing out of it.[3] The cover of the first American edition shows a woman looking over the Tiber.[4]
