After a car accident in 2006, Sam Tyler was up in 1973. Sam's 21st Century attitudes make him a fish out of water in this world of clunky technology and old fashioned policing. And nothing seems more alien than his new boss, DCI Gene Hunt, who believes in gut instinct and, all too often, sheer brute force. Then Sam discovers a connection between a murder in 1973 and the kidnapper in 2006. Could solving this case be the key to getting home?

Sam decides he has to embrace this world - for now. But then he discovers Gene is planning to plant evidence to secure the conviction of Kim Trent, an elusive criminal. Shocked by Gene's attitude to crime-solving, Sam releases Trent. But when a young woman gets caught in the crossfire as a result of Trent being freed, Sam is forced to question his methods. Can he and Gene put aside their differences and find the evidence to nail Trent?

Tyler has visions of someone disrupting his life support system in 2006, and encounters who he thinks is the same assailant in 1973, running a gambling syndicate and protection racket. Recognising the man as a killer he failed to stop in the future, Tyler is prepared to go to any lengths to make sure his life is not threatened and the man doesn't kill his original victim.

On an assignment to return a career safe breaker from prison for further questioning, Tyler, Ray and Chris are attacked by robbers and the man who they were taken in for questioning is broken out. Is a local gangster to blame, or is there more going on than meets the eye... specifically, was the crime actually arranged by Gene's old mentor? Meanwhile, Sam tries to break in the first black detective in the department, a man who will later become Sam's mentor when he first joins the police force.