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.

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.

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.

The team is on the hunt for major vehicle thief Jed Wicklow, but when a car chase leads to his death, Gene stands accused of causing it through reckless driving. Alex is adamant that there was something wrong with Jed at the wheel and wants to prove that the crash wasn't Gene's fault. The deceased Jed was a Romany gypsy, and hostilities run high on the camp as CID heavy-handedly try to uncover the circumstances of his death. But in an investigation that's already met with resistance, someone in the police force also appears to be standing in their way.

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.

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.

Animal rights activists have threatened a series of attacks in London and the first victim, the daughter of a commercial laboratory owner, is in hospital. Gene orders his team not to sleep until those responsible are behind bars. Their first stop is a prison where Robin Elliot, a known animal rights campaigner, is serving time for killing a scientist in the 1970s. Alex is convinced that Robin knows about the planned attacks, but with no contact with the outside world, there doesn't appear to be any way for him to be involved. Robin's eerily prescient knowledge of the future makes Alex think that he could be involved not only with the case, but with her own fate; having heard the voices of ambulancemen, Alex worries that hope is fading for her survival in the present day.

The team investigates the armed robbery of a fundraiser who has been travelling across the country in a bathtub full of baked beans to raise money for Children in Need. Alex thinks that a crime reconstruction on Police Five will do the trick, but Gene prefers some old-fashioned police work.

When a violent burglary occurs at Alex's in-laws' house, she comes face-to-face with their son Peter, the 14-year-old future father of Molly! Alex is desperate to help Molly's grandparents all she can, but Gene wants a big collar to bury the press stories of police corruption, and dismisses the case as trivial. When the fingerprints from the crime scene reveal the burglar was George Staines, a notorious gangster, now supposedly dead, Gene realises this could be the catch he was after. Alex remembers hearing stories about the burglary, and is convinced that she would remember if the culprit was as infamous as Staines. Gene is determined to uncover the truth and get the headline he deserves. Alex finally meets the mysterious man who has been leaving roses in her apartment and office. He tells her that she can go home to see her daughter again, but involves her becoming corrupt.

After a dead body is found in the canal it is identified as Colin Mitchell. Alex is certain that the dead man's wife Donna is not telling everything and she is determined to uncover the truth. Back in 2008, Alex has surgery to remove the bullet from her brain.

Gene discovers that an undercover operation to catch several drug dealers is taking place on his patch without his knowledge. Determined to take control Hunt blows the cover of an undercover operative who turns up at CID and is eventually placed under his protection, yet it seems someone on the inside is twisting things to help the drug dealers stay out on the streets. Meanwhile, the deceased police officer continues to haunt Alex. Could he actually be her key to getting home?

When a dead man is found in a Soho strip club, it looks like a sex game has gone wrong. So when the deceased is discovered to be a police officer, Gene and Alex are ordered to keep the case under wraps.

Alex soon realises she has not returned home after all, and wakes up in 1983. Gene is on the run, and DCI Jim Keats has arrived from Complaints to investigate CID following the shooting. Newly-promoted DI Ray Carling leads an investigation into the kidnapping of a young girl, and sets up a sting operation. Alex decides that she will have to discover the truth about Gene if she is ever to get back to her own time.

Gene and the rest of CID are feeling the pressure to stop a series of politically motivated arson attacks in the lead up to the 1983 General Election, after a military compound and a polling station are set alight. DCI Jim Keats announces his plans to monitor the way Hunt and his team work while trying to turn each member of of the team against Gene. Elsewhere, Alex continues to mount her investigation into what really happened to Sam Tyler in 1980 and is struggling to work out why she is being haunted by the young police officer.

CID find a body buried in concrete as they investigate a drugs drop at a building site. Alex thinks she is getting better and will soon wake up in her own time. Working on the case though starts to clash with her wish to be back home.

When DCI Gene Hunt's former Manchester colleagues, DCI Litton and DI Bevan, turn up on his patch he immediately smells a rat. They're in pursuit of northern comic Frank Hardwick who's wanted for stealing 2,000 pounds from the Police Widows Fund. However, their desperation to track him down leaves Gene and DI Alex Drake suspicious of their real motive.

A face from Gene's old stomping ground of Manchester shows up called Jackie Queen. Jackie is a reporter who is investigating teenagers who traveled to London from the north and have disappeared.

A severed hand is sent to Fenchurch station. Discovering that several women have been murdered, Alex decides to join the dating agency they all used. Alex tries to discover the truth about Sam Tyler's death, but Gene is obstructive.

All hell has broken loose at Fenchurch East prison; the inmates are rioting and DCI Gene Hunt is ready to go in all guns blazing to teach the lags a lesson. However, things don't go to plan; the riot team are hugely outnumbered, and in the chaos of the retreat someone is left behind.

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.

DCI Jim Keats has almost finished his report into DCI Gene Hunt and his team, but he's still pushing DI Alex Drake to find out what really happened to Sam Tyler. When reports come in of a disturbance at an ANC illegal drinking den Gene heads in all guns blazing. The men at the club are quick to dismiss the disturbance as nothing, but when DI Ray Carling spots blood on the floor and discovers a dead body, it leads Gene into a murder investigation.

After Alex catches an infection back in 2008, she knows the doctors think she wont pull through. Distance grows between Alex and Gene and their relationship is put under the greatest strain yet.

DCI Gene Hunt and his team are investigating a diamond heist following the murder of three London gang members. But DI Alex Drake is distracted and, with encouragement from DCI Jim Keats, she decides to pursue her own investigation to the bitter end - did Gene Hunt murder Sam Tyler? When Gene discovers that Alex has gone, he races after her leaving Ray Carling, Chris Skelton and Shaz Granger to plan an ambitious sting operation. As Gene desperately tries to reach Alex before she discovers the truth, Chris, Shaz and Ray's world completely falls apart. It's time for Alex and the rest of the team to find out the truth about Gene Hunt...