Watched the first episode of "The Serpent" which I did not enjoy (they did that thing where they tried to catch your interest by telling the story in such a way as you don't know what's going on ... because you won't care for any of the characters or be interested in the denouement otherwise), switched to Traces which I thought was better (on Ep 2, won't win awards so far but it is "good enough" to watch).
I came here to recommend The Serpent which we've just finished watching.
Although the to-ing and fro-ing in the time line requires careful attention, it's a gripping, and very worrying, tale very much of its time (1970s).
I liked the way they'd interleaved period footage into the drama. The comprehensive roundup of the current status of the main characters was welcome and we'll done.
As someone who was on the very outer edges of the fringes of the European end of this world its all very credible - and maybe that's why I enjoyed it so much.