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 buys a Welsh dresser at Charlie Gimbert's auction, and hidden inside it he finds a rich Arab head-dress, festooned with gold ducats. Catesby, recently out of prison and the son of the dead man whose property was being sold at Gimbert's, says he was promised the dresser. Lovejoy sells it back to him, but without the head-dress. Catesby is soon looking for Lovejoy armed with an axe. He is in good company, as one of Her Majesty's Inland Revenue officers is also after Lovejoy.

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.

The wife and brother of a man killed with a fabulous pair of Regency duelling pistols engage Lovejoy to find them and thus bring about the downfall of the murderer. In the process, Lovejoy puts Jane's life at risk and challenges Dr La Grange to a duel.

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.

Needing a break from Charlie, Lovejoy takes a job for a few days at a new antiques market in Norwich owned by a client of Jane's. He soon realizes the boss is a con-man and sets out to expose him. Along the way, he also tries to trap a second crook who is selling fake paintings.

Lovejoy finds a bundle of old love letters hidden in the back of an antique clock. He quickly falls for the owner, but are the letters genuine? Under the name of 'Captain Lovejoy', he sets out to find the answer.

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.