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.

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.

Blackton's investigation gets closer to the truth.

The murder of Mrs Thornton makes Eric the prime suspect for both deaths, but conflicts with a parallel investigation into the landscape gardening business where Eric works threaten to undermine both cases.