There was so much potential for sci fi story arcs - both per-episode-short and per-season-long. So much could be done with the mechanism of come back alone, the element of extraction/disappearances in 60ies, even with the idea of "agency" and "secret prison" awaiting. Instead we were served with... procedural police drama? They just come back, without explanation of how, how they feel about it and how the world looks to them and all of the imbeciles try to do the same crimes, with the only "gripping" element being "the crime style is really old"? WTF? Why? It's a wasted idea, it's not done, it's like if Lost was about passengers of an airplane getting stranded on mysterious island and then all we see is them talk about politics, badmouth celebrities, get suntan, try to make fire and do some spider eating challenges in each episode when Ant & Dec appear out of nowhere to announce voting out. You don't do time travel Alcatraz sci fi mystery series to do some lame donkey "first time chick + fat guy" Dempsey & Makepeace routine for quarter of a season? What on earth is this?