Boyd and his team struggle to find the truth behind the murder of a prominent Home Office adviser, when a petty criminal is acquitted of the crime. Once a prominent feminist activist, victim Katherine Reed had attacked the establishment at every opportunity, only to later switch sides. Boyd's progress on the case is hampered not only by a Home Office audit, which means the team will be shadowed throughout, but also by the fact that the original investigation was conducted by one of his old flames.

Whle facing a surprise audit from the Home Office, DCI Boyd (Trevor Eve) and the team try to continue their investigation into the murder ... but as they go on with their inquiries at Whitehall, they quickly discover the atmosphere to be very dark and secretive.

When a convicted killer is cleared at appeal for the murder of his adoptive father ten years previously, Boyd is not convinced that the man is innocent. But the only way to find out is to track down the rest of the family - and with a big inheritance at stake, both parties appear to have a lot to hide..

Following the murder of Mark Lovell's cousin, the team establish that Mark has a watertight alibi, and the search for the real murderer narrows down to the remaining family members.

Their investigation into the two remaining family members is further complicated by the discovery of drug dealing and involvement in the witness protection scheme.

A criminal is about to be released, the team is sure he is a serial killer. They enter in a race against the clock to prove their suspicions to prevent his upcoming release.

A criminal is about to be released, the team is sure he is a serial killer. They enter in a race against the clock to prove their suspicions and prevent his upcoming release.

The plot thickens as Rivelli and then Harris confess to the three cold case murders. Boyd remains suspicious though - who was the real murderer and what has Jensen got to do with it all?