The OAP detectives return to investigate a fresh batch of unsolved crimes, beginning with the murder of a palaeontologist at the Natural History Museum. After a bit of digging, the team discover the victim was a respected but outspoken scientist with a knack for rubbing people up the wrong way - and when they discover he was strongly opposed to the museum's sponsorship deal with a large fuel company, the old dogs soon have plenty of suspects.

Amanda Redman stars, with guest appearances from the late Trevor Bannister (Are You Being Served?), Lucy Brown (Primeval) and Natasha Little (Spooks)

The UCOS team reinvestigates the murder of an unnamed vagrant strangled on a tube train 15 years ago when DNA tests on a suspect in a warehouse robbery reveal him to be the dead man's son.

The UCOS team are drawn into a world of immigration loopholes, Albanian gangs and family feuds when they reinvestigate the death of an unidentified male discovered on farmland outside Waltham Forest in 1996, in what appeared to be a crucifixion.

New information links the unexplained death of a market trader to a series of drug rapes in east London - but with that case still ongoing, Ucos are unable to question the chief suspect, so they have to look into their victim's past in their search for clues. Gerry soon finds a likely culprit in the shape of the market inspector who clamped his car, while Sandra has problems of a more personal nature when her hated mother arrives for a visit.

After psychologist Samantha Gerson shows up at UCOS to conduct a study on older men in the workplace, she ends up getting a mixed reception. Samantha also wants a favour and asks Pullman to look at her brother's case. Darren Gerson was the victim of a hit and run in May 2006 which left him with a serious brain injury and complete memory loss of anything about his life before the accident happened. Darren now is convinced that he is still a target because of the package he was carrying at the time.

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.

A woman is sent anonymous emails from someone claiming to know what happened to her husband Phillip Mackenna, a prominent scientist working on cold fusion who disappeared while on a train to Paris. As the team investigate, DAC Strickland receives a warning from Whitehall.

As part of his initiation into a motorbike gang called The Braves, Reece Chapman plans to murder the rival gang member he believes killed his father Eddie, the former leader of The Braves. Desperate to stop Reece, his girlfriend Stephanie Parr turns to UCOS for help in solving Eddie's murder to prove he's targeting the wrong man.

The investigation of the murder of Christopher Collins, who was listed on a website as missing by a former employer, meets a dead end until it is revealed that he was in the witness protection programme. Meanwhile, the team wonder what effect the upcoming cuts to the police force will have on UCOS.

The team reopen the case of zookeeper Zac Halsey, originally thought to have been mauled to death by a tiger, when blood evidence discovered in his lodgings suggests he was killed before he was found in the tiger's enclosure.

Jack announces that he he has decided to leave the team, but before Sandra, Brian and Gerry can question his reasons, Whitehall figure Stephen Fisher shows up with one of his secret cases featuring the unsolved murder of a woman dating back around a hundred years. With only 24 hours to solve it, the team attempt to find time to get to the bottom of Jack's surprising decision and attempt to persuade him not to leave.

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.

Retired DI Steve McAndrew from Glasgow joins the team to reopen one of his old cases when the DNA of a woman who went missing as a teen turns up at the scene of a petrol station robbery.

The team become concerned that undercover police operations may have been compromised when the body of a computer expert who worked with the Met turns up under a false name at a teaching hospital.

The team investigate the death of a 16-year-old tennis star who fell—or was pushed—from a penthouse balcony after she lost an important match to a rival.

DS Pullman breaks the rules to explore a possible cover-up at the Foreign Office.

The team investigate the murder of an East German immigrant, but they only have his mysterious final words to work with. As they attempt to piece together his remarkable story, Sandra attempts to gain the trust of his estranged daughter.

McAndrew and Standing are sent to Scotland by Strickland for a week, to help the Glasgow Police try and establish a new UCOS section led by DCI Fiona MacDougall. While there, they end up being caught up in a cold case from 1993 featuring the murder of bookie James Soutar.

Thirty years ago, Strickland and a group of his associates, including Stephen Fisher, were involved in a covert operation on behalf of MI5. Now, someone is trying to kill all the members of that group and Strickland turns to the UCOS team for help.

UCOS re-open the case of Sean Docherty, a talented young poet whose burnt body was discovered ten years ago in the scrapyard of a known gangster. While Standing is convinced that the murder is related to Docherty's criminal connections, Lane is sure that the answer lies in his poetry.

Lane's future at UCOS is threatened by a death in custody which emerges from his past. Meanwhile, the discovery of a mysterious gun in the Thames re-opens the unsolved 1998 murder of a playboy shipping heir and leads the team to the Rock of Gibraltar.

The team unlock over three decades of secrets and lies on the Rock of Gibraltar and find the link which solves the murder of a playboy shipping heir from '98 and a young local boy from '82. With both cases solved, they return to England where Lane faces a disciplinary hearing, dragging up a death in custody from his past which threatens his career in UCOS.

Brian Lane knows his days at UCOS are numbered. Meanwhile the team investigate a 16-year-old murder of a young mum by her criminal husband that could be a miscarriage of justice. However Gerry Standing feels very strongly that the conviction should not be called into question.

As Lane comes to terms with life after UCOS, Esther asks him to help one of her book club friends find her missing brother - but will his nose for the truth get him into further trouble? And how will his former colleagues cope without their most dogged sleuth?

A young woman's paternity test leads to the reopening of a notorious murder case from the seedy underworld of 1980s Soho in which the prime suspect was mysterious ex-jazz chanteuse Angela Gold. Meanwhile in UCOS, feathers are ruffled when recently retired police officer Dan Griffin joins the team.

When blood-stained clothes belonging to Simon Belgrade, missing for five years, are uncovered in a London forest, UCOS find themselves trying to solve the conundrum of what seems to have been the perfect vanishing act. Standing finally faces up to a childhood fear, while Griffin is a comfort to Pullman as she passes a milestone and McAndrew makes a big decision about his son.

When the team investigate the death of an MP's researcher and find themselves in hot pursuit of a mysterious Bosnian woman, Strickland introduces Pullman to a war crimes prosecutor who proves to be more than helpful to their case.

Pullman seizes the chance to solve a murder that she believes is linked to her first ever case, and the team start putting together a jigsaw puzzle of suspects from a photograph taken in a London park in the 90s. Eventually faced with increasing pressure to hand over the investigation, Sandra makes a huge decision, which is going to change UCOS forever.

With Sandra having left, the team wait to meet their new boss, and Sasha Miller wastes no time fitting in and getting on with her first Ucos case. It features the murder of an Italian immigrant on a west London allotment 25 years ago.

Miller is faced with a dilemma when the investigation of a corrupt senior officer calls into question the conviction of Edward Monroe - who she believes to be guilty of murdering her old work partner. Pre-empting an appeal, UCOS must carry out preliminary investigative work for Strickland.

Family ties affect both Gerry Standing and Sasha Miller. While Sasha is forced to work with ex-husband Ned as he fills in for Strickland, Gerry returns to his roots in Bermondsey to help arrange his daughter's wedding. As a consequence he is thrown into a case involving the possible murder of an architecture student who is also the grandson of an old friend.

Meanwhile, Danny Griffin has been on an FBI course in reading body language.

The team investigate the unsolved killing of brilliant young doctor Lydia Dryden in a case that takes them into the two very different worlds of public and private medicine.

Danny Griffin is bereft when daughter Holly leaves home to start university, so his UCOS colleagues throw some fun distractions his way. And he might even be about to acquire a pet...

The team looks into the death of a terrorist 30 years previously after his daughter receives an anonymous note claiming he was murdered - an investigation that takes them right back to the Greenham Common anti-nuclear protests.

Meanwhile, Sasha agrees to go for dinner with her ex-husband Ned, which he is hoping will lead to a reconciliation.

When Steve McAndrew's teenage son Stewie is arrested for drug possession, he finds himself face to face again with his ex-wife Tricia as they try to save the boy from a downward spiral. And after a distressed dementia patient escapes her care home to report a murder, the team look into the disappearance of a policeman, possibly murdered but missing since 1956...

Tension mounts as Ned and Sasha are forced to work together when the body of a film critic found in a sewer is thought to be linked to the 20-year-old murder of a concept artist, David Straka. As the team interview Straka's contemporaries, groupies and assistants, looking for possible connections between the deaths, they find themselves immersed in the macabre world of the occult. And Griffin's expert knowledge of the history of London and in particular the hidden Fleet River, proves invaluable.

The team investigate the death of a personal trainer who had belonged to a Roman reenactment society and discover a gang selling illegal steroids, but the motive for murder may not be all it seems.

And Danny Griffin starts to become attracted to his forensic pathologist colleague Fiona Kennedy just as he receives some troubling news about his wife.

UCOS want to talk to a Turkish girl who is found working illegally in Dalston, regarding a unsolved murder from 2009. The landlord of a pub, Richard Gibson, died in a fire and the case had remained unresolved. The team meet the landlady of the pub, Joanna Gibson, who is also Richard's widow. His best friend, David is also someone of interest, especially when the team find out the French champagne he is selling, is actually sparkling wine produced in Britain. Sasha enters the team into a 5-a-side football competition.

While investigating the murder of 55 year-old interpreter Agnes Bradley, the UCOS team get a partial DNA match from a teenage boy who once threw a brick onto a motorway as a dare. They interview the boy to see if one of his male relations could be the murderer, only to discover that his mother was raped and they could be looking for a rapist-turned-murderer. Agnes was a chess enthusiast so Gerry Standing and Steve McAndrew interview members of her local club while Sasha Miller and Strickland investigate leads from Agnes’s working life, where they meet a Chilean diplomat with a possible axe to grind. Steve McAndrew’s elderly father is dying, so he brings him to a London hospice for his last days.

When cold-crime enthusiast Ellen Barker is murdered, a photo of Dan Griffin is found at her house. Griffin is interviewed by the murder team, who realise that Ellen was a friend of his. The senior investigating officer assigned to Ellen’s murder investigation is DCI Grace Mackie, one of Sasha Miller’s contemporaries from their Hendon training. Griffin is convinced that the last case Ellen was looking at could lead to her killer, and heads to Minchampton, where a woman called Sally Tunstall was murdered 25 years ago by local lad Dougie Haynes.

A mix tape from 1983 is discovered, containing the voice of a teenage girl who was murdered shortly after it went into her school's time capsule. Griffin becomes convinced that the girl is reading from a speech secretly prepared for the Queen to broadcast in the event of a nuclear war.

Meanwhile Sasha is distracted by a romantic entanglement with a charming record shop owner and Gerry is dreading his future son-in-law Robin's stag night, which promises to be something very special...

Gerry feels spooked following the discovery of UCOS's latest victim, a policeman, whose body has lain untouched under a basement for the last 30 years. Accusations of police corruption and underhand dealings start to surface causing Gerry to face up to some skeletons in his own closet.

Gerry attempts to clear his name before his enemies catch up with him. Sasha and Steve get Fiona's help to examine the evidence against the clock. Danny takes Gerry on the run as they look for the proof they need to prove his innocence.

Ted Case is welcomed by Danny and Steve into the UCOS office in Sasha's absence, but for all his wealth of experience, they aren't sold on his superstitious quirks. The team take a look at the case of a brutally murdered vicar who received racist hate mail in the lead up to his murder.

Ted leads an investigation into the apparent suicide of a city trader in the 80s.

With Sasha back on fighting form, UCOS investigate the death of a cricket prodigy.

The team investigate the bloody murder of a political activist 15 years ago.

The boys' investigations take them to a lookalike agency whose top acts were found dead.

The movements of a rare stamp could hold the key to the murder of a private investigator.

The team investigate when a skeleton is uncovered in the foundations of a swimming pool.

UCOS investigate the case of an alternative medicine practitioner bludgeoned to death.