DI Alex Drake is taken hostage and shot, and wakes up in a brothel... in 1981. Rescued in a police raid, she quickly recognises DCI Gene Hunt and his team from detailed reports made by DCI Sam Tyler about his own trip to 1973.

Gene is determined to address London's growing drugs problem, and has targeted city playboy Edward Markham as the brains behind the operation. Alex suspects Arthur Layton, the man who kidnapped her in 2008. Could Layton be the key to her return to her own time?

DCI Hunt is determined to keep a lid on protests against the London Docklands development. When a suspected member of the London Liberation Front is arrested, Alex asks her mother, a lawyer, to defend him. Meanwhile, Prince Charles is marrying Lady Diana Spencer and the in-crowd is partying at the Blitz Club.

Fresh from a successful drugs bust, Gene and the team investigate a prostitute's rape allegation. A dangerous serial attacker may be at large, but the case is hampered by an unreliable witness and the suspect's connections.

CID investigate a murder, and discover a plot to sell stolen nuclear secrets to the Revolutionary Workers Front. When Gene and Alex get trapped in a secret Government facility at Edgehampton, the temperature rises.

Gene and Alex discover that a notorious pimp and drug dealer has a major firearms deal in the pipeline. In an attempt to locate him, the team go undercover in a gay club, and Ray goes beyond the call of duty to get his man.

An armed robbery leads Gene to Chas Cale, a criminal he tried to bring down in Manchester. But when Chas reveals his alibi, Gene begins to wonder if he is past his prime as a DCI. Alex sends Ray and Chris undercover at the local pub in order to solve the case.

Alex is determined to prevent the murder of her parents in a car bomb attack. Gene, meanwhile, is determined to give a good impression to a visiting Lord Scarman, but the station is still dealing with the aftermath of a Gay Pride demonstration.