OK, I have to admit now, I'm getting a bit frustrated with this series. They seem to have left it way too late to explain the construct properly and convincingly. How on earth are they going to get through a crime being solved, a revelation of exactly who and what Summers is, get Alex home and resolve the Alex/Gene relationship in one hour? And I've checked my series link on Sky+; it definitely ends next week, and IIRC it has been unequivocally said now there will be no third series.
In series one, the underlying narrative of Alex uncovering the process of her parents' death worked well and peaked nicely in the last episode without feeling too strained. This time round, they don't seem to have calculated as well, and have been struggling to make the underlying trajectory / deeper meaning to it all both clear and plausible. Have to say, that seems like the price of the rather indulgent period 'jokes' taking over on this run; it's been less coherent as a concept drama (sorry to go all Radio 4 but...)
And above all that, they have let the Gene/Alex flirtation drift badly. I have to differ from some other posters: I've thought for a few weeks now they have been phoning in this aspect of the script: a few 'suggestive lines' in each episode, usually in Luigi's, but no actual situations that might move the relationship on, like the getting trapped in the reseach facility (was it? It was the one where the both had to take their clothes off 'cos it got really hot and Green Door was the background music - brilliant ) or the Vienna-backed Gene striding through the window, shattering glass, to rescue Alex. Where have all those set pieces gone? They really made me feel that something was smouldering and about to happen. Lately it's all just felt like a damp squib.
I say all this in love, really I do, because on the whole I've really enjoyed the entire idea. But I am now worried it's fizzling into either something wildly improbably, or romantically disappointing, or both. I hope I'm wrong.