When Corvinus receives a letter, with a tantalising PS, from his adopted daughter, Marilla, mentioning there might have been a murder, he hot-foots it to Castrimoenium at once.

Not that everyone agrees that Lucius Hostilius was murdered. Poison was apparently the means of death, but Lucius was terminally ill: it was only a matter of time. Although he hasn't any official investigative status, Corvinus can't resist doing a little amateur sleuthing. And he has barely begun when two other corpses turn up and he is formally on the case.

Lucius had been suffering something of a personality change because of his illness, so there is no shortage of suspects among friends and family whom he had antagonised. But Corvinus goes up many a blind alley before arriving at the heart of the mystery.

As we follow Marcus Corvinus, clue by clue, on his twelfth case, we allow ourselves to be pleasurably diverted by rumours of Meton's love life - and by an authentic recipe for fish pickle sauce . . .