The TV series Ashes To Ashes is another brilliant time-slip TV show, which is a spin-off from Life On Mars.
To cut a long story short, DI Alex Drake, who was studying DCI Sam Tyler's suicide in 2006, gets shot in 2007 London, and wakes up in 1981 London, working alongside the legendary DCI Gene Hunt from Life On Mars.
In 1981, Sam is missing presumed dead, and Gene Hunt is now with the Metropolitan Police, driving an Audi Quattro and still being as politically incorrect as ever (but he has mellowed a bit).
We get many of the old characters back, in particular the great DCI Gene Hunt, one of the funniest TV characters in recent years with his comments.

As the series is still ongoing, little has been revealed so far. But with rumours of various "secrets" and "revelations" being put to rest, I'll be watching for a while yet...