One of the most unusual, subtle, and philosophically sophisticated series to grace the small screen!
Our first glimpse of DCI Sam Tyler isn't very promising. He's coolly efficient at his job, but doesn't seem to derive anything more than a grim satisfaction from it. He's dating a subordinate, which tells you everything you need to know about his social life.
Then he is thrust into a bizarre situation: after a near-fatal car accident, he finds himself in 1973. Why 1973? He doesn't know. Complicating Sam's already impossible situation is that some of his senses (especially sight and touch) indicate that he is in 1973, while others (especailly hearing) indicate that he is lying comatose in a 2006 hospital bed.
Lost, confused, and frightened, Sam attempts to work out what has happened to him... and how to get home to 2006. If he can't trust his memories or the evidence of his own senses, what can he trust?
Very slowly, Sam begins to change. He smiles. He rediscovers and reconnects with what he's lost--a family cat, football matches, then his mother and father. We see that 1973 Manchester is, economically, a much bleaker place than 2006 Manchester... but it's also warmer, more organic, all earth tones in contrast to sleekly modern 2006, which is filmed in cool blues and greys. Sam's 1973 bedsit is hideous, a garish riot of oranges and browns, but it's also more lived-in than his spotless white-and-chrome 2006 flat. But 1973 isn't a lost paradise, either; "Life on Mars" doesn't hide 1973's flaws or film it through a rose-coloured camera lens. It shows us what we have gained, and what we have lost along the way. We see that the reforms in policing that stifled Sam and his colleagues in 2006 are a direct reaction to the police abuses Sam sees in 1973.
Sam's 2006 knowledge and sensibilities are both boon and liability. He's had a thorough grounding in criminal psychology and modern forensics, and he's extremely well-acquainted with drug crime, which is only just beginning in 1973. But he never seems to realize the extent to which casual racism and sexism affect life in 1973. He treats WPC Annie Cartwright, the lone woman in the department, as an equal--which she appreciates--but doesn't understand why everyone else doesn't. He sees in her a talented cop being underused; he's right, of course, but he thinks that all he needs to do to further her integration into CID is to draw attention to her abilities. To no one's surprise except Sam's--certainly not Annie's--the men react with undisguised contempt.
It's this sort of subtle contrast between 1973 and 2006--the weaknesses inherent in being from the future, as well as the strengths--that really set "Life on Mars" apart.