Having hired Eric Catchpole as an apprentice, Lovejoy sets out to unravel the meaning of a Japanese firefly cage.As Lovejoy and Eric are in hot pursuit (on Eric's motorbike) of a lovely lady with something they want, they hit a pool of water in the road and give a drenching to Jane (Lady Felsham), who is busy unveiling a plaque. When, later, Lovejoy rings the doorbell at Felsham Hall, complex chemistry begins, and Jane is soon showing Lovejoy around her attic...

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.

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.