Gerry is approached by Ralph Paxton, a boyhood friend who became a career criminal and was imprisoned for a jewel robbery. Ralph believes that his grandson, architecture student Jake was murdered by his partner in crime Wayne Pelham because the boy discovered the loot hidden in a tower block due for demolition. After interviewing Jake's brother and his college tutor the team locate Pelham, who informs them that others knew about the hidden jewels. The team eventually end up with two prime suspects, both of whom believing that they were acting out of principle, though one is the killer. Gerry also has to overcome his dislike of the solicitor to whom his daughter Caitlin is getting married.

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.

Thirty years after the death of a suspected terrorist, the man's daughter receives an anonymous note claiming he was murdered. Clues lead the team to the Greenham Common antinuclear protests of the 1980s.

Elderly dementia sufferer Nancy leaves her care home to report that her policeman husband Jimmy, who disappeared in 1956 was actually murdered. Harry Page, an old friend of the couple, reports that Jimmy had gambling debts and got into a fight the night that he died. Sasha takes Nancy back to her old house where she recalls Jimmy's violence and jealousy. A grim secret is discovered in the bedroom wall, in turn leading to the solution of the murder. Meanwhile Steve is called to the police station when his son Stewie is cautioned for minor drug possession, which brings him into conflict with his ex-wife Tricia. They do not part on good terms.

When film critic Oliver Houghton's corpse is found in a sewer Sasha is reluctantly forced to work with Ned as Oliver had been a witness in the unsolved case of gay artist David Straka two decades earlier. Both men were drowned and Danny sees the river Fleet as a link since it featured in David's last project. David's friend Ruth Shireen tells the team that David and Oliver got involved with the occult due to the unpleasant Cyril Watkins though Cyril, now Cecily after gender realignment, explains that there was no harm intended. However a woman playing the part of a sacrificial victim in David's film about the mysteries of the Fleet accidentally died. A trip to the sewers locates her corpse and Sasha beats Ned to finding out her identity and solving both cases.

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.

Illegal Turkish immigrant Asye Ersoy was working as a barmaid in 2010 but disappeared following a fire which killed the pub's landlord Richard Gibson. Now she has been traced but denies committing any crime. The pub's former pianist Jason claims that Richard was happily married to wife Joanne and she endorses this. Relations with his brother Gavin, a slot machine vendor who wanted to buy the ailing pub, were less harmonious whilst Joanne believes Richard was having an affair with Asye but did nothing about it. The identity of Asye's actual lover and a scam involving the sale of cheap wine, dressed up to appear as of better vintage, are both uncovered before the real killer is unmasked though Gerry and Steve regard the case as a welcome diversion from Sasha's attempts to enter them in a five a side contest.

The team notice that DNA from teen-aged market trader Spencer Rogers, arrested for throwing a brick on the motorway, matches that of interpreter and chess club member Agnes Bradley, murdered in 2010 and when Spencer's mother Kelli tells Sasha that Spencer was the result of her being raped by an unknown man it is apparent the rapist is the murderer. Suspects include Jeremy Powell, who, according to chess club captain Viktor Proust, smarted because he could never beat Agnes and Chilean diplomat Carlos Alvarez who had Agnes black-listed after one of her translations warned students against his womanizing. Whilst the rest of the team is busy trying to catch the murderer Steve is occupied with bringing his hate-filled dying father Robbie to a hospice in London.

After an amateur sleuth is murdered, a photo of Danny is found at the scene. It turns out Danny was her friend, and he vows to find the killer. Clues lead to a 25-year-old murder and a trip to the countryside.

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.