Set in Rome between August and October, AD 73, the novel stars Marcus Didius Falco, informer and imperial agent.

The title alludes to the song "Three Coins in the Fountain" as well as to the macabre discovery which triggers Falco's investigation.

Falco arrives home in Rome with Helena Justina and Julia Junilla Laeitana, his new baby daughter, and barely have time to settle in before being subjected to a welcome-home party.

Anacrites, who is rather annoyed at being muscled out of his stolen case, sends four men to beat up Falco and Petro.

After continuous reconnaissance he has two problems: First, Claudia Rufina, the heiress from A Dying Light In Corduba and the new fiancee to Helena's brother Aelianus, has vanished, and second, a slave called Thurius has been identified as the murderer.

The book ends with Falco telling Petro his wife went out with another man, and later receiving a visit from Anacrites.