This new show is a sequel to the original, British version of Life on Mars, in which London cop Sam Tyler was seemingly transported back in time to the 1970s. In Ashes to Ashes, Tyler’s male chauvinist boss (ably played by Philip Glenister) and his sidekicks return, but the protagonist is now Alex Drake, a single mom and criminal profiler who has been zapped back to 1981. If you can suspend disbelief enough to accept its complex premise, Ashes to Ashes (which, like Life on Mars, takes its title from a vintage David Bowie song) is even more fun than its predecessor. Keeley Hawes (MI-5) is both plucky and sexy in the lead role. Saturday, March 7, at 9 p.m., BBC America