Lovejoy sets out to help a young woman to trace a pair of Meissen figures which she sold to raise cash for a drug habit. When he comes across evidence of a double-cross by Charlie Gimbert, he decides to get even.

A robbery at the local museum seems to be connected with the death of a local forger, and Lovejoy goes on the trail of a hoard of Roman coins in the Isle of Man. Two Americans are also after the coins.

Sam Wendell, an old forger, dies of a heart attack while being pursued by a mysterious priest, leaving behind one of his small forgeries. Sam had told his wife it was the key to a fortune, and the priest soon tries to break into the Wendell house. Lovejoy aims to unravel the puzzle, by way of helping Sam's widow (who's left with very little) to recover anything of value. Along the way, Lovejoy dresses up as a priest.

Lovejoy travels to Venice to investigate the murder of a friend. The dead friend had bought a painting Lovejoy believed was a fake. In Venice, he is drawn into an ambitious art swindle, and identical twins Caterina and Lavinia are behind the scam.

In Venice, Lovejoy gets a job working for Caterina and Lavinia, with a view to busting their scam, and meets a Scottish forger called 'Lucky' Luciano. Lovejoy and Lucky together unravel the mystery of the Island of Rats.