Sam Tyler is the primary character of Life On Mars. He is portrayed by John Simm. DCI Sam Tyler was hit by a car in 2006 and wakes up to find himself in 1973 as DI Sam Tyler from Hyde, transferred to DCI Gene Hunt's team.
In Life on Mars
Sam is constantly fighting to get back to his own time, trying to wake up of the coma he's in.
He is frequently visited by the Test Card girl in a red dress who speaks to him and tells him of his situation in the future.
He is quickly attracted to WPC Annie Cartwright, who later becomes a WDC. He tries to enforce his modern approach to policing on his team. His techniques are often ignored by most members of the force, but Gene seems to take them on board, and DC Chris Skelton pays close attention to how Sam works.
He has a strong rivalry with DS Ray Carling, who would have been due a promotion if Sam hadn't arrived.
Many of the crimes he has to solve have links to him in the future. Sam gets to meet the younger version of his mother and gets to meet his father again, who ran off when he was a young boy.
As the series progresses Sam becomes more accostomed to policing in Manchester 1973, adopting a few of Gene Hunt's habits, while Gene takes onboard some of his. The bond between Gene and Sam grows stronger through the series.
He finally discovers in order to get back he has to sacrafise Gene and the rest of the team including Annie. At first he takes the option and returns back to 1973.
The bar manager in 1973 once told him:
"If you can't feel anything then it isn't real"
This is significant because when Sam returns to the future and cuts himself he is unable to feel it. He records his story and sends it to a fellow female officer and friend who specialises in interesting phycological experiances of officers. He then throws himself off the Police station Skyscraper, returning to 1973 to save his team.
The series ends with him and Annie kissing, and Gene pulling him away on another case. The Test Card girl is seen playing with the other children, then runs up to the camera and smiles before hurrying back to the others.
In Ashes to Ashes
Sam never appears in Ashes to Ashes, but it is mentioned that he married Annie.
Sam's situation is explored in more detail in the third series. Although no body was ever found, it is suggested that he and Annie are both dead. There are later suggestions that Gene himself killed Sam. This is however disproved when the more supernatural element of Ashes to Ashes kicks in, revealing this world to be one for Police Officers who died unsatisfactory deaths.
Sam and Annie were both ready to move on so Gene took them to the pub and left them there (the pub symbolises the after life).