UCOS investigate into the death of a policewomen-whose case was closed years ago-following the recovery of the murder weapon from a lake.

The discovery of a fake painting in the Queen's art collection sends the UCOS team on a hush-hush mission to uncover the forger. Their investigations swiftly uncover a trail of high class frauds and suspicious deaths, but also lead to suspension for one of the squad.

NOTE: In Scotland This Episode Was Shown On Sunday 11th April Due To LIVE Sportscene Football Being Shown

The UCOS team investigate the murder of a young peace protestor, killed at the outskirts of a nuclear base in 1984, and realise that they may be in danger of exposing a Special Branch cover up.

The members of a prestigious golf club come under suspicion when the UCOS team investigate a child murder.

When a missing person case which Lane originally investigated gets re-activated, he's determined to crack it. But when the team swiftly uncover another two mysterious disappearances, they start to think they've got a serial killer on their hands.

Deputy Assistant Commissioner Robert Strickland is the new boss in charge of the Unsolved Crime and Open Case Squad (UCOS). He asks the team to look into the death of David Barrie, a top barrister found in his car in 1980 after being bound and gagged.

Tabloid editor Chris McConnell asks Sandra Pullman to help him prove celebrity chef Kitty Campbell killed her drunken husband Bertie 40 years ago at the height of their 60s TV fame.

Attractive widow and probate assessor Elise Allen asks Halford to find the rightful owner of a large, uncut red diamond, worth £15 million. She found the rare jewel in a flat rented by John Newman who died in 1982.

Lane indulges his obsession with fishing when UCOS investigates the case of two boys abducted from a fishing lake in 1979, believing it could be linked to a recent spate of snatches near the M25.

The Home Office pathologist asks the team to identify the remains of an unidentified woman, whose remains were found back in 1987. These remains are the only body that he was unable to identify. With his help and that of his attractive assistant, not only must the team identify the body bits, but how she died and who killed her.

A car in which five years ago a teacher was murdered is returned to the victim's husband. Pullman re-opens the unsolved case, hoping her team can track down the dead woman's secret lover, and a clue soon leads them to a male prostitute. Pullman had worked on the original case and been troubled throughout by the lack of emotion shown by Nancy's husband Stephen

The murky death of Joe Walsh, General Secretary of the Crane Driver's Union, whose body was found in the Thames in 1975, is reinvestigated. At the time of his death, Walsh stood accused of stealing money from the union's account. The team find themselves at the centre of a political minefield, with suggestions of misappropriated union funds, MI5 involvement and a union leader whose threats of strike action were gravely threatening the national interest.

When a serial dog killer starts stalking local parks, the team are reluctantly forced into taking on the case.

The vicious criminal Chopper Hadley, who has been back in the country for a week, is searched for by the team. However, Halford is viciously intimidated and the squad start to realise the full danger of their target. Desperate measures are used and Brian is sent undercover to get Hadley once and for all.

A young woman insists that the suspicious death of a local librarian was because of witchcraft and the team are drawn into the world of magic and the supernatural. A series of strange events occur and they are put under increasing pressure. The squad gets convinced that the supernatural exist and struggle to remain cynical.

The team are on the case of the ice cream bandit, an armed robber who's targets were the ice cream vans of two feuding ice cream manufacturers in the mid 1990s. The battle between the two families erupts into violence, so UCOS decide to track down the bandit and stop the conflict once and for all.

Pullman struggles to keep the boys in line as their chequered pasts begin to be revealed. Halford is determined to nail a vicious criminal who has so far eluded him and in doing so he puts himself in grave danger. Standing receives a surprise visitor which shocks him. Pullman is increasingly frustrated and weighs up an opportunity that could end her time in UCOS.

The future of the team is threatened and without having that to deal with, Sandra has to take drastic measures to prevent Jack from exacting revenge against the man who killed his wife Mary. Sandra also has the added benefit of trying to keep Jack’s actions from shady new recruit DCI Karen Hardwick while working on a 10-year-old murder case.

Sandra's private and professional worlds become intertwined when her mother has a fall and goes into a care home - but the establishment is revealed to be a scene of a suspicious death a year earlier.

When an armoured van is discovered at the bottom of a lake, the team makes a link with the murder of a women 17 years ago.

The team reinvestigates the 1950s murder of a young wages clerk at Battersea Power Station.

Richard Dunne was hanged for Frederick Tully's murder, but his granddaughter, Hannah, is waging a campaign to have Dunne posthumously pardoned.

The discovery of a suitcase containing used fivers in the attic of the Tully home sheds new light on the case, revealing a possible blackmail plot.

A trace on the used fivers reveals that they should have been destroyed in the Battersea Power Station furnaces back in the 1950s, but were actually being saved by Douglas Murray, a friend of Tully's.

It also becomes clear that the Battersea furnaces were being used to destroy other sensitive documents as well as used bank notes.

When the team discovers a classified document relating to a massacre of civilians carried out by the British Army in Kenya, they uncover a blackmail plot spanning more than 50 years.

When Brian's dog finds a body, it prompts two people to confess to murder. It turns out that the body is over 600 years old, so Sandra, Jack, Brian and Gerry must discover why the pair took responsibility for a crime they couldn't possibly have committed and if they are the perpetrators of other killings.

Elsewhere, Strickland is rather keen for them to solve an even more tricky mystery that is closer to home.

The news that Sandra's father, a DI, killed himself while under investigation for corruption, throws into doubt everything she believed in.

Her mother, Grace , is in hospital following a stroke, and she wastes no time in confronting her, but she doesn't get the answers she's looking for.

Unfortunately, her father's service records provide Pullman with some revelations she may never come to terms with.

Meanwhile, Christy Berlin asks the team to look into the death of the man she's recently discovered was her biological father - ringmaster The Great Miraculob. But will the investigation at Spingles Circus be enough to distract Sandra from feeling betrayed by her colleagues?

Gerry meets his heroes, the 70s rock band Bad Faith, when the team investigate the death of its lead guitarist. It is over 30 years since the group split up, however, and the ageing rockers do not quite live up to the legends Gerry remembers.

Meanwhile, determined to prevent UCOS from disbanding, Brian finally tracks down Jack and tries to persuade him to return.

The team return to the 1992 case of actor Michael Austin, shot dead by his wife on stage during the opening night performance of Death at the Masked Ball. Already a man down when Halford goes AWOL, the case looks like claiming another member of the team as Lane embraces his newfound love of acting and the theatre.

The team reinvestigates the murder of a popular DJ who died live on air after an arson attack at 80s music station Roxy Radio. Lane is determined to find the missing Jack Halford when Pullman and Standing threaten to quit rather than work with a new team member.

Jack and Strickland form an unlikely alliance that sees them break the rules to find out why a British soldier died while taking part in a Ministry of Defence medical trial. With three of the man's colleagues now suffering from psychological, drink or memory problems, the team consider whether he died as a result of the experiment, or if he was a victim of an Army cover-up.

UCOS reinvestigate the death of a wealthy financier when a psychic tells the dead man's daughter that she needs to resolve some unfinished business on her father's behalf. Deeply sceptical of Sebastian Carter's 'gift', the team set out to prove him a fraud, but Pullman struggles to dismiss him as a con man when he reveals a conflict involving her own late father.

Brian finds the library card of cold case victim Dr Richard Symes, leading him to reinvestigate the death of the professor, who died after falling from the roof of his college three years previously. Sandra and Gerry interview Symes' widow, who believes principal Jeremy Ventham drove her husband to suicide following a conflict over teaching methods.

After being released from jail, notorious paedophile John Davies admits to the abduction and murder of a child 25 years previously. Suspicious of his motives, the detectives reopen the unsolved case in an unusual attempt to prove his innocence, reinvestigating the boy's disappearance while on a demonstration with his left-wing activist parents. Guest starring Adrian Schiller (Being Human) and Samantha Bond (Outnumbered)

When the gun used to murder a talented young boxer 11 years ago surfaces in an armed robbery, UCOS are drawn into the darker side of professional boxing in a case that causes conflict and friction among the team.

Sandra's old flame DCI Larson, head of the Met's arts and antiques squad, asks the team to reinvestigate the murder of antiques dealer Mal Baxter. His death was originally thought to be the result of a burglary gone wrong, but new evidence suggests Baxter was a police informant while conducting underhanded deals.

The team are called in to reinvestigate the disappearance of PE teacher Jason Bowe after a body is found on the perimeter of the elite public boarding school where he was employed. The investigation has come at a really bad time for the school, which is getting to welcome a former pupil, the Rt Hon Geoffrey Parkes MP, for the opening of a new computer centre.