UCOS reopen the thirty year old murder of porn king Jim Hockney when his daughter Sara reveals that a DNA test proves she is not his daughter. Her mother Jane cannot provide any answers as she and Jim both had several sex partners. Jim's girlfriend at the time, singer Angela Gold, was charged but acquitted of the murder and now seems to have disappeared. Brian's replacement Dan Griffin arrives, albeit late and is initially treated with hostility by Gerry, who thinks he is a spy. Nonetheless Dan tracks down Angela though in the meantime Sandra learns that Jim's brother Colin sold Jim's porn empire very shortly after his death to his main rival Gavin Reason. Furthermore Jane and Gavin were lovers, Gavin proving to be Sara's father though he was unaware at the time. However it is Gerry's collection of some of Jim's old films, supposedly confiscated by Vice Squad, that identifies the murder weapon and leads to the culprit. The case closed the team watch Angela perform at Ronnie Scott's Jazz Club.

Following the 1997 General Election Ben Ransley, a young researcher for successful MP Liz Jackson, was murdered and the case is reopened on the discovery of £40,000 in an off-shore account in his name. Ben's best friend, arrogant lobbyist Eddie Trenton, gives Sandra a photo of Ben with his girlfriend, who turns out to be Hana, the Bosnian wife of tycoon Peter Russell, and she also disappeared in 1997. French policeman and former war crimes prosecutor Max Clement comes to London and tracks down Hana, whose whole family was killed in the Bosnian war. Hana believes Ben, with whom she was set to elope, was killed by the man who got her to England and introduced her to Peter but Dan discovers that Ben was in a position to leak information about a government arms deal, which would have been injurious to certain people. This solves the case.

Fresh from her successful SWAT raid on a group of Russian gangsters DCI Sasha Miller arrives at UCOS to replace Sandra. She is friendly and informal but initially fails to win over Gerry, who misses Sandra. Her first case involves the twenty-five year old murder of Italian Allesandro Manzini, reopened when a knife is found at the allotment he once tended. Massimo, whose son married Allesandro's daughter Giulietta, tells the team that there was anti- Italian feeling on the allotment, especially from two World War Two veterans, whilst lorry driver and druid Ray Barlow is also suspect, having disappeared after the murder. This suspicion is heightened when Giulietta and Ray admit to an affair but Dan's research into wartime Italy changes everything, leading to a confession. Sasha's private life, however, does not run so successfully.

In 2010 trainee doctor Lydia Dryden was found dead in her flat after visiting Bar 393 night club. Neighbours reported a possible stalker lurking outside the building but her parents, both surgeons, do not recognize him from the Identikit picture. Married Laurence Devlin, another surgeon, denies having an affair with Lydia though it transpires that he is her actual father, which her mother Monica has kept from husband Hugh. Lydia's sister had a drug habit and Lydia was suspected of stealing from the hospital medicine cabinets to help her. then the stalker is revealed, a man whose wife died during an operation performed by Laurence and Lydia. He denies killing her but helps lead the team to the true murderer.

In 2008 body-builder Mark Rix died of a heart attack, seemingly caused by a surfeit of steroids. Now a sword is found in his old lock-up, which decapitated an unknown man just before Mark died. Mark was a member of Imperium, a group re-enacting life in Ancient Rome and Steve and Sasha learn from Imperium members Julia Kane and Tim and Tessa Dugdale that he believed himself to be Marcus Rex, incarnation of a gladiator. Forensic scientist Fiona Kennedy identifies the murder victim as a Romanian gangster who sold illegal steroids and the team deduces that Rix used Imperium's foreign dates to import them. After confessing to Fiona that his estranged wife Sarah is in a secure unit, having tried to kill him and his daughter, Danny goes undercover at Imperium, where he recognizes Julia as another undercover cop. Eventually the team learns the truth about both men's deaths from Julia before Danny goes on a date with Fiona.

Over thirty years after school-girl Amy Taskerland died at an end of term disco a time capsule is unearthed, containing a tape where she expresses fear of Alec. Neither her father William or best friend Harriet can identify Alec though Amy's headmaster falls under suspicion as he was having an affair with Amy whilst dating teacher Carla O'Brien. Then Danny discovers that Amy appears to have been reciting a speech to be used by the queen in event of nuclear war which leads to the identity of Alec and in turn to who killed Amy. Gerry meanwhile has a surprise on his future son-in-law's stag night whilst Strickland springs an even bigger surprise and Danny successfully plays Cupid for Sasha.