After a man is found wandering Jersey nude and suffering from memory loss, Susan's eccentric aunt, yachtswoman Belle is asked to make a no questions asked trip to France but refuses. Jim discovers that the mystery man, Smythe, has actually murdered his wife, though Smythe genuinely cannot recall it. His friends, however, are extremely dangerous and will stop at nothing to get him off the island. Jim calls on Belle's help to stop them.
Grumpy software designer Jarvis McLeod receives death threats through his computer and his wife Monica's dog is poisoned. Then the speaker deputising for him at a conference is blown up. McLeod is not popular but the chief suspect seems to be John Logan, the embittered ex-partner in his business - though he has an alibi. Bergerac wonders if McLeod is actually behind the so-called death threats. Certainly the culprit seems to be somebody close to home.
Deborah is being stalked and receiving sinister phone calls. The culprit is Sydney Sterrat, whom Jim had sent down for six years for arson, during which time his wife committed suicide. Believing that Jim is still married to Deborah, Sterrat sets out to get revenge, holding her, Kim and Charlie at gun-point in Charlie's house. Jim sets out to rescue them all on his own.
Susan is selling Carol Miles's late grandmother's bungalow but she cannot understand why shady builder Tim McVie, camp mainlander Toby Newsom and surly young Kirk Barnett are all so eager to pay tens of thousands of pounds over the asking price. Is it because they believe that stolen jewels never recovered are buried in the ground over which the property is built? Or is it connected to the development plans Charlie has for the adjacent land? Either way one of the potential buyers is an obsessive, with a secret, and that places Susan in great danger.
Three well-meaning animal rights activists, including Kim's boyfriend Kevin, liberate three monkeys from Gaines' research unit, unaware that one has the deadly Marburg virus. It bites Kevin and also attacks a holidaying couple. Jim and his team must hunt the animals down without putting the whole of the island in a panic but after Kevin dies and the monkeys are caught, one of the activists, possibly infected herself, goes on the run.
Philippa Vale approaches Jim after being threatened by a thug who claims she has a notebook listing the members of S.P.A.R.T.A, an ultra-right wing organization though Philippa denies all knowledge. She does, however, recall robbing industrialist Sir Clive Hamer of a diamond choker some months earlier and deduces that he is the group's leader. When she sets out to find out more from Sir Clive without telling Jim, she lands herself in hot water from which Jim has to save her, but fortunately they have a valuable ally in Hamer's wife.
Shortly after womanizing financier Peter Hughes has disappeared, along with seventy thousand pounds from his firm, French Inspector Dupont asks Jim to identify a body in France, that of Jean Pichet. Pichet would appear to be Hughes, keeping two wives who know nothing of each other. But when the corpse is identified as that of a third person again, Jim and Inspector Dupont have cause to wonder why their man has the need to do a disappearing act.
Alec Price dies after drinking poisoned wine whilst being received into the local Masonic Lodge. At his wake another mason dies, seemingly a random victim, having eaten a poisoned cake. Jim learns that the lodge were raising money to build a community hospital on the island but the funds have disappeared. Jim knows that the killer was one of the other masons but the culprit's motives turn out to be very strange indeed. The case solved, Jim is reunited with Susan, who, fed up at being neglected because of his work commitments, has had an affair with another man.
Tony Bragg, suspected fence in a huge diamond heist is pushed to his death from his London flat. Bragg had visited Jersey some while earlier and Scotland Yard ask for Jim's help. Then Philippa Vale arrives on the island with Bragg's associate Ormond, who is also killed. Philippa tells Jim that Ormond asked her to rob three local worthies, one of whom double-crossed Bragg and stole the diamonds. As the pair of them work outside the law to locate the culprit - who also murdered Ormond - they find that nobody can be trusted.