Blackton's investigation gets closer to the truth.

Detective Chief Constable Blackton begins an investigation into both the Cripps shooting and the investigation into James Lampton, which drags up problems for both Commander Blake and D.C.I. Hedges. Matters become worse when Blackton begins looking into the Commander's affair and the subsequent arrest of Lampton, while she also has to deal with the death of her sister.

A post mortem examination shows that Donald Griffith died from a blow to the neck, and not by drowning, supporting DCI James's theory that one or other of the women in his life had decided to profit from his death. Dutch detective Van Hauten arrives with a possible solution, and designs on Commander Blake.

The perfectly-preserved body of a two-year-old girl is found in a sealed oil drum in the basement of the derelict Elliston psychiatric hospital. Commander Blake assumes the role of senior investigating officer from DI Doug James, creating early conflict within the team as they set about investigating former patients and staff. As the team closes in on two particular suspects, there is a clash with the drugs squad, who are running a parallel investigation into one of them.

DAC Sumpter asks Commander Clare Blake to take charge of the investigation when Joan Hall, mother of former DS Brian Hall, is found beaten to death in her own home, and Brian is accused of the murder. When his prints are found on the murder weapon and his blood also found at the scene, Clare believes it to be an open-and-shut case, but DCI James refuses to accept that his former colleague could ever be responsible for such a crime. Meanwhile, James' wife Zoe goes into labour, but an argument with a fellow-to-be proves to be the action which begins a chain of terrifying events, when his new baby is abducted from the maternity ward.

A priest is brutally beaten and stabbed to death on an east London estate, where bad feeling between residents and police threatens to undermine the investigation. Suspicion falls on local boxing protege Jimmy Bannerman, but progress is hampered when Doug and Clare demonstrate very different attitudes to the brutal competitiveness of the sport. However, a vicious attack on a fellow detective forces them to form a united front. Boxer-turned-actor Gary Stretch stars as Bannerman's…

As the investigation continues, suspicion shifts from Jimmy Bannerman to Terry Donnolly when an eyewitness puts him at the scene of the murder and information on his troubled childhood comes to light. Doug has been coping with his own emotional events at home, but realises he may already know who the real killer could be.

When DCI Janet Chambers (Connie Hyde) goes into labor, Commander Clare Blake takes charge of the investigation into the death of a two-year-old girl found on the site of a now abandoned psychiatric institute. The girl has been dead for several years, but her body had been stored in a tightly sealed drum and is well preserved as a result. She also has a cross branded onto her chest. The pathologist's report is inconclusive, so the team start to check medical records of former patients.

Eric Thornton and John Littlewood figure prominently in hospital files, but when it's confirmed that Littlewood has died, the police focus all their effort on Thornton. A dark history of mental problems and violence related to them, Thornton stands out as the prime suspect in the girl's murder, but when his own mother (Celia Imrie) is murdered in cold blood, James isn't convinced that Thornton is responsible for either death.

Acting on instinct, Clare digs deeper only to find that the truth is more shocking than any of them could have imagined. The investigation into James' missing baby leads Clare to Fiona George, a fellow mother at Zoe's maternity classes. However, her judgement proves to be her downfall, as she commits a desperate act in a bid to reunite James with his baby. As the consequences of Clare's actions bite, rookie DC Marion Randall's hunch leads her to the real abductor. Clare is tested both personally and professionally - but has she gone too far this time?