A new team of detectives, the Cold Case Squad, is put together to re-examine evidence of unsolved murders using advanced technology. In their first investigation DCI Peter Boyd has a second go at nailing the murderer of Alice Miller, a young girl who disappeared five years ago. Trouble is, the perpetrator is as keen as Boyd to act again, and abducts another girl.
A young woman, Marina sets fire to an abandoned car in a street and takes photographs of it as it burns. Boyd walks by and tackles her to the ground, attempting to shield her from the possible explosion. He later learns that Marina's father died in a car accident a few years earlier in that spot, and Marina refuses to accept that his death was an accident. Although not officially a cold case, Boyd is intrigued and reluctantly agrees to investigate. Frankie runs forensic tests on Marina's father's car and proves that he was still alive after the crash and could have escaped. The answers they uncover may mean that the danger to Marina is much greater than any of them had suspected.
Boyd has Marinas uncle, Mike Coleman and her mother Gwen brought in for questioning while Frankie searches the house. The team find the items that were recovered from the car nine years ago and suspect that Perry Coleman was being blackmailed by Rod Brogan, a friend of Perry's. Boyd has the body exhumed and the DNA results suprise everyone
Workmen are burrowing in the crypt of a Catholic church when they come across the skeletal remains of a young man buried in concrete. The squad sets about trying to pinpoint the identity of the body, which was buried with the accoutrements of certain Catholic rituals. Even more oddly, there is a message in Braille buried with the corpse, which tums out to be a passage from one of St Paul's letters to the Corinthians The team suspects that the body was never meant to be discovered.
Boyd and the team decide to reopen the 25 year old case of Annie Keel, a woman who was tried and convicted of a double homicide solely based upon her own confession. Boyd doubts the validity of the conviction, and decides to dig deeper to possibly discover what really happened. Why did Annie confess? Did she really commit murder, or was she covering for someone else?
The Cold Case team is forced to enlist the help of a psychotic serial killer named Thomas Rice, AKA "the Gambler" (because he left playing cards at the scenes of his murders). The one woman who escaped death at his hands, the cool and poised Dr Clare Delaney, gets a dreadful reminder of her past ordeal and a fearful shock when a playing card is flung at her car windscreen as she sets off to make a house call on a wet, windy, dark night. The team look again at the Gambler's crimes, prompted by Boyd's unshakeable belief that Rice had claimed other, hitherto undiscovered victims.Boyd - who has personal links to the case - and Grace decide to use detective constable Amelia Silver to lure a confession from Rice.
Boyd and the team continue to begrudgingly rely on serial killer, Thomas Rice's assistance on the case, while also trying to protect Dr. Delaney from experiencing her terrifying ordeal once more at the hands of the copycat assailant. It becomes apparent that he might have help on the outside, so it's crucial that Boyd confronts one of Rice's intended victims, Dr Delaney, to find out what went on during her captivity. Why did he spare her life?
Boyd and the team take on the task of infiltrating the dark underworld of London's gangland crime families when Harry Newman makes a deathbed confession to 12 "unauthorised killings". Dr Grace Foley is intrigued by this strange expression but Boyd and the rest of the team are tempted to dismiss it as the meanderings of a dying man. Until, that is, forensic psychologist Frankie Wharton discovers that Newman did not die of natural causes, but has been murdered. They soon realise there's a lot more to Newman than they imagined. Added to all that, there's a link to a famous fifties trial in which a gangster was hanged for killing two policemen.
Boyd and his team struggle to find the truth behind the murder of a prominent Home Office adviser, when a petty criminal is acquitted of the crime. Once a prominent feminist activist, victim Katherine Reed had attacked the establishment at every opportunity, only to later switch sides. Boyd's progress on the case is hampered not only by a Home Office audit, which means the team will be shadowed throughout, but also by the fact that the original investigation was conducted by one of his old flames.
When a convicted killer is cleared at appeal for the murder of his adoptive father ten years previously, Boyd is not convinced that the man is innocent. But the only way to find out is to track down the rest of the family - and with a big inheritance at stake, both parties appear to have a lot to hide..
Following the murder of Mark Lovell's cousin, the team establish that Mark has a watertight alibi, and the search for the real murderer narrows down to the remaining family members. Their investigation into the two remaining family members is further complicated by the discovery of drug dealing and involvement in the witness protection scheme.
A mummified body sends the Cold Case Squad back to the sixties and to a Notting Hill house which had been featured in a film as the location for a murderous fight between gangsters. Renovation works at the house in the present day reveal more bodies behind the walls. The film starts to appear not so fictional after all. Things get even more complicated when Spencer tells Boyd that he and his family lived there when the events took place.
Boyd and the cold case team investigate the unsolved murder of a World War 2 conscientious objector. In 1948 George Western was found in his living room with a nine-inch nail through his head. When his grandson Adam finds new evidence and organises a media campaign, the case is reopened. Then the body of elderly William Davis is found in similar circumstances. And Grace uncovers the identical killing of Norman Taylor in 1961. The team discovers that Taylor and Western were in the same regiment during the war and trace surviving members to try to solve the murders.
The Cold Case Squad discover that the victims were a group of friends who were all in the same army regiment during the war. It seems the murderer is killing as an act of revenge.
Boyd and his team face a race against time after a skeleton found in a condemned garage triggers a tragic chain of events. The skeleton is that of garage owner, Gerald Doyle, an Irish terrorist who went missing in 1981. An unexploded car bomb found at the scene points to terrorist activity as the cause of death. However, Doyle’s parents produce a set of his diaries, which reveal that he was actually a mole for the British intelligence services.
The Squad begin to feel like they are being watched, and their fears are realised when they find unauthorised surveillance equipment. It is revealed their victim may have not have been as guilty as they once thought and when a person Boyd questioned as a part of the investigation commits suicide, they realise a missing link between her and a assassination. Boyd gets 36 hours to get to the bottom of things before the security services take over.
In 1990 - Jason and Cindy, two 5 year-old twins disappear from their home, and even after a nationwide search is launched, they are still not found. Thirteen years later, Jason is found in a hospital suffering from injuries he sustained in a car accident. But where's Cindy? Boyd and the team set out to find her. Mel Silver is trying to find her biological mother
The team try track Jason as they work out how the twins were taken and why. They link the twins disapperance to a Dr Roper, who knocked Jason down. They unravel his past and find out some dark secrets. The squad work out who Cindy is now and try find her before its too late
A man staying in a "halfway house" for released prisoners uses a gun - that is revealed to have been used in contract killings years ago - commit suicide. The gun is later stolen from Frankie's lab. Investigations reveal that the gun could have been used by a hired assassin in 9 murders over the last 30 years. Boyd is taking Anger Management.
When the gun stolen from Frankie is used in another murder, the Squad suspect the victim's gopher. It is revealed the first murder could have been a case of mistaken identity. Frankie and Grace begin to get creeped out by the effects of Boyd's Anger Management!
The Squad investigate the murders of two males who had the word "Sorry" carved into their backs. The latest victim has a brother linked to Organised Crime, so three other officers are brought in, which Boyd takes an instant dislike to - except Greta. The new faces create tension in the office and the team cannot trust them. As the case goes on, they begin to realise that it could be leading to a paedophile group.
The case continues as we learn of the death of D.S. Dave Marvin. Marvin has been found dead in his car with the same markings of sorry on his back. Throughout this episode we learn that Greta is hiding something from us and who is the mysterious old man who keeps turning up every time a body is found???
A young woman with a history of psychiatric problems kills her family by setting the family home on fire. She admits to the crime, but claims that she was coerced in to doing it by a mysterious character known only by the name 'The Shepherd'. Her psychiartrist links her case to similar cases and gets the Cold Case Squad involved.
Boyd and the team continue to investigate the arson case and the other two other possible crime connections to 'The Shepherd'. Will the team discover this person's true identity or will it all turn out to be a part of the imagination of a mentally ill woman?
A mummified body is discovered in a disused airliner that has been parked in the desert for 6 years. There are indications of a link to an armed robbery at Heathrow Airport six years earlier, and a murder at around the same time. Our team gains two new members. DS Andrea Stephenson takes over for DS Mel Silver, and the new mad scientist is Dr Felix Gibson.
Spencer goes undercover as a prison inmate to investigate the possible reasons for the murders from the man convicted of committing the crimes. To Spence's dismay, the man (who is too scared to say anything about what happened) commits suicide before he can be coerced into revealing who the real killer is.
The team re-investigates the death of a teenage boy who was found on a building site some years ago, drowned in concrete. Part of a human ear is found in his stomach, linking him to the dumping of another seriously injured teenager in a hospital at around the same time. The ground on which the dead teenager was found belongs to a Catholic abbey which is soon to be dissolved, and the abbey owns a shrine which might contain evidence and has to be dismantled - a task which falls to the unwilling Stella Goodman.Meanwhile, new forensic scientist Dr Eve Lockhart makes her mark on the case.
Continuing the investigation of the death of a teenager whose body was found in concrete on a building site years ago. The injured Joe McDonagh finally wakes from his coma - but how much light can he throw now on a boxing bout which went badly wrong long ago?Meanwhile, there are surprises in store for Boyd and Jordan.
Boyd receives an anonymous package in the post – a Nazi ceremonial dagger. Attached to it is a Cold Case number, linking it to the unsolved murder of a young girl in May 1945. It seems that Mel had been working on the case before her death, what does this mean for the Cold Case Team?
As Ben goes missing, Boyd and his team try to force the truth out of a confused David. Boyd grows increasingly close to Sarah, and Stella travels to Poland to investigate the true story.
After a women running naked along a country way is picked up there are two cases to solve. The first one is to find out how she got there, a complicated task because she suffers from memory loss. The second case goes back quite some years as her DNA was found in a strange cold case with two bodies and a sword.
After the shooting in the hospital in which Stella is wounded the involvement of the priest becomes clear. With the shooter killed there is no chance for interrogation, but his body provides a useful clue linking back to the cold case. In the meantime things become even more complicated when a women turns up who looks a lot like the one in the hospital.
When Eve's new boyfriend Stefan is being vague about his past she puts her skills to use and uncovers something she rather wouldn't have. Unsure about the next step she turns to Boyd for advice, initially he promises support. But once the facts become clearer Boyd and Eve want to follow a different path.
Boyd has to break in a new team member of equal rank, Detective Superintendent Sarah Cavendish, a high-flyer recently grounded by a hushed-up failed operation.After the empty and abandoned car of banker Donald Rees is discovered threee years after he went missing, Boyd decides to take on the case in an effort help the man's family find some closure with their lives.
After a woman is discovered stabbed in the eyes and incinerated in her car she is identified as Claire Somers, a neglected child who was taken into care, then later kidnapped in 1986 at the age of seven. Robert Fenchurch had his eyes stabbed out on the night Claire was kidnapped as her abductor fled the scene. The team soon find out that Claire had snatched 15-year-old Abigail Harding, who was found locked in a hotel room.