Confectionery magnate John Briggs, head of an ailing empire and at odds with union leader Kenny Barber, is found dead of an apparent heart attack in a hotel bedroom. He was about to sell his company to millionaire Emmett Schwartzman. His sole heir is long estranged daughter Geraldine, to the chagrin of his brother Phillip, whom Geraldine appoints as company director. Young police pathologist Jack Hodgson claims Briggs was murdered, believing he had been with a prostitute, and is sufficiently persuasive that Leo recruits him to replace Harry, now working in New York. Briggs' right hand man Trenter pays off escort Deanna Collier, who is actually Geraldine's daughter and had just tracked Briggs down. Geraldine gives Deanna a charm bracelet but soon afterwards the girl is murdered.

As Nikki discovers that Deanna was not Geraldine's daughter but an opportunist out to fleece Briggs, Schwartzman decides against buying the confectionery firm. Interviewd by DS Gold in Nikki's presence Geraldine explains that she was raped by Phillip Briggs as a teenager and her baby given away. John Briggs' legal adviser Annette, who found Deanna, expresses unease to Tranter about the deception and is later found murdered. Geraldine is arrested but the pathologists, aided by Jack's wheelchair-bound mentor Clarissa, uncover the truth though the killer never makes it to court. Geraldine is, however, reunited with her real daughter.

Leo attempts to help Mark Benson,whose wife Shona was imprisoned for killing their baby and begins to spot discrepancies in the expert witnesses at the trial. Petra Smith is abducted and imprisoned in a remote farm building at the same time as two women's corpses are discovered in a basement. The officer in charge, Chrissie Reid, once has an affair with Jack until he accused her of corruption in order to get an arrest. The two women have been injected with a toxic substance and Chrissie and Nikki visit the factory that makes it. The suspicious actions of scientist Lucas Ballinger cause them to follow him to the hide-out where a man called Hearns has imprisoned Petra and is about to inject her though Lucas is scared as he had not realised that anybody would die. Hearns kills him and sets fire to the building and Chrissie pursues him, leaving Nikki inside the burning building.

Nikki escapes the burning building but Petra dies and Leo's examination shows she was injected with anthrax. Jack identifies one of the basement victims,also injected,as being Lucas Ballinger's wife and Nikki surprises him at the scene of the murders though he flees. He goes after Hearns and later Chrissie finds Roper,who was the accomplice in taking the virus out of Ballinger's workplace, dead. The team must locate Ballinger and find out why he allowed his wife to be a victim as well as stopping him from committing a terrible revenge which could endanger thousands of lives. Leo meanwhile successfully gets Shona's conviction overturned.

Pub landlord Roly Henderson is accused of stabbing to death his wife Joanne in her sleep and cutting off her little finger. DI Kate Warren is anxious to convict,under pressure from her father a deputy chief constable,to further her career but Clarissa and Nikki find proof of Roly's innocence and his little daughter Emma recalls seeing a strange man in the pub. Nikki visits Simon Marshall,convicted of killing his wife Eleanor four years earlier as her finger was also chopped off after death. Simon tells Nikki his wife was murdered by a biker and Nikki and Jack find evidence to support his story. Nikki believes this man killed Joanne,Eleanor and a third victim,Imogen Lane,who married the older policeman Alan who rescued her from her pimp when she was a teen-aged prostitute. Alan was convicted of his wife's death but is now released. Imogen's mother Edith hated Alaan,believing he killed her husband as well as her daughter,whom she feared he would harm. Edith is unaware that she is being shadowed by Janice Masters,a single parent who also has a little finger missing.

Jack discovers that Kate,under pressure from her corrupt father,has tampered with evidence to incriminate Roly Henderson and demands she accept Nikki's opinion that Alan Lane killed all three victims. They visit Anne Percival,the retired officer who sent lane down even though Imogen's body was never found - in the event because,thanks to Anne,she was given a new identity as Janice Masters. Nikki finds out that Lane has killed nine women who all has histories of domestic turbulence so that their husbands were blamed. After Anne has fatally tried searching Lane's house the team must stop him before he can get to Janice.

The body of young Colin Connor is found in an attic at a former hospital now marked for residential development. He had been stealing metal but was locked in the attic by his accomplice who then fled. The culprit seems to be Derren Blackburn whose father lies for him when D.I. Cherry visits with Jack. At the same time, Leo is asked by distraught father Tom Hancock to conduct a post mortem on his son Peter, who, Tom is convinced, died because of electrical towers outside his window. Leo is surprised to find that Peter and Colin had an identical kind of kidney dysfunction. James Embleton, a government minister who begins dating Nikki, is in charge of the hospital conversion, and is visited by the sinister David Loader, who warns him of Leo's investigation into Colin's death. Leo and Jack look for proof of toxicity at a farm near the hospital, but are evicted by the army. Leo contacts George Ryder, who owned the farm, and they agree to meet at the hospital as George has an important revelation, but tragedy intervenes.

After Darren is killed trying to escape, his father tells Leo of the boy's recent personality change, and examination of his body shows he had Fanconi's Syndrome like Colin and Peter. Nikki tells James that Leo suspects a conspiracy, especially after George's daughter has spoken of the haste with which the family was moved from the farm and the poor compensation they received. James now comes to see that his father, Sir William, and his henchman Loader - who Jack proves killed George Ryder - are involved in a cover up. After being falsely discredited and suspended from work, Leo joins Tom to investigate the woods near the farm and hospital and discover what the cover up had been trying to hide. As Nikki asks James how much he knew, Tom sets out for revenge.

The team goes to Afghanistan at the request of sergeant Scott Lambert to see if human remains found at a charity water supply project are those of his brother Daniel,missing for five years and presumed murdered by the Taliban. On arrival in the country they encounter a road block and land mine and Jack's mistrust of the army does not go down well with ex-military man Sean,who heads the private security force. Nikki finds some bones but her examination is interrupted by a Taliban attack,repulsed by Scott's men. Project leader Fawzia believes it was motivated by opposition to Western influences,exacerbated by the pathologists' arrival. Fawzia shows Leo a ruined building where Daniel was apparently imprisoned and Jack finds proof of his being shot in the back of the head. Nikki however worries herself over the treatment of the Taliban prisoners,who include an English fanatic,after one of them is killed by Sean and his death made to resemble suicide.

The team continue to investigate the death of Daniel Lambert and make a significant discovery that changes the whole situation.