With the recent release of Cabinet papers under the 30-year rule, Jack pushes to reopen the investigation into the death of Joe Walsh, a left-wing union leader. His body was fished out of the Thames in the mid 1970s and his death put down to suicide, but it was clear that the Cabinet wanted his antics stopped, and Jack wonders if someone might have taken those wishes a little too seriously. There were rumors that Walsh had fiddled the union books, and several of his contemporaries are convinced he was disposed of by MI5. Meanwhile, Brian decides to stop taking his medication, with expected results.

In 1989 32-year old Charlie Hayes, a stock market trader, fell to his death, a presumed suicide, from his office building near Tower Bridge but a blow up photograph in a retrospective art exhibition reveals a background figure who pushed him.Cash-strapped Steve takes advantage of insider information as the team interviews Charlie's former girlfriend and colleagues, prime suspect being obnoxious Kevin Dodds, whom Charlie exposed as a rapist and the team brings him in. However the rape gives him an alibi for the murder and Danny and Steve discover that Charlie was sacrificed to prevent him disclosing certain anomalies within the company's trading.