The corpses of five illegal immigrants are found in a meat lorry by Customs at a Cornish ferry terminal. Driver Eddie Sowden goes missing and claims ignorance when the police locate and arrest him but Wycliffe is convinced he is lying and resolves to winkle out the truth.
Wycliffe and his team are called to Bodmin Moor where a resurgence in corpses suggests that the so-called 'Beast of Bodmin Moor', a black panther which escaped from a zoo, and has a reputation for mauling livestock to death, has been active in slaying locals. Wycliffe, however, takes the view that the so-called beast is a convenient cover for a murderer with genuine motives and his theory is put to the test when Doug Kersey ventures onto the moor on his own and fails to come back.
Jamie Yelland is found dead, shot through the head on land owned by Dan Hobden, and his house is ransacked. Jamie had been a diver, obsessed with a sunken treasure ship, carrying silver coins, allegedly never found, and had had dealings with local historian Donald Treloar, similarly obsessed and murdered with the same weapon that killed Jamie. Wycliffe believes the treasure was found and that both men were killed by an interested third party.
After he is accused of breaching the hated E.C. fishing quota, Joe Mawnam's trawler sinks and his mate and best friend Don dies. Wycliffe and his colleagues establish that the boat was scuttled for the insurance money but their professional instincts are at odds with sympathy for fishermen whose livings are being destroyed by foreign bureaucracy and ultimately must act to prevent another tragedy.
Psychiatrist Stanley Malvern's wife Dawn is murdered whilst he is out with his dog. He has no financial gain from the death and helps the police investigation as a profiler. Lucy is sure the killer is a woman and she is right. Disturbed neighbour Annabel Naylor fits the bill but Wycliffe believes someone else set her up with a motive.
When a dead baby is found in a cardboard box on a church steps, Chris Matthews comes forward to say that he has seen a pagan sect, led by the unsympathetic Dr. Dayton, saying, "Bring forth the child" in a midnight ritual. Lucy investigates the sect but the real key to the mystery lies with Wycliffe's boozy friend Bill, whose wife has just left him and who is staying with the Wycliffes with his withdrawn teenage daughter.
Magistrate George Pender's body is found hanged in woods but Wycliffe does not believe it was suicide. Disgruntled fisherman Jimmy Yates, whose wife left him after Pender jailed him, is a suspect, but Lucy is intrigued by the attitudes of the Pender family, his son Neil and girlfriend Jane, whose mother Pat, like Pender, once lived in Plymouth. As Pender's hostility to the relationship between Jane and Neil is exposed, so is a shocking secret from his past.
Ellie Creed, whose father has just been imprisoned, is found strangled and the pathologist notes a similarity with unsolved serial killings a decade earlier. Chief suspect is Hugh Samford, in the frame before and now back in Cornwall after a long absence who has no alibi for Ellie's death or that of a second young woman. Kersey gets close to married Inspector Jill Gillespie, who liaised with the Creed family, making it more shocking when the true killer is exposed.