OK, pedant points first. The intelligent reptiles previously known as “Silurians” are of course, nothing of the sort. Quite the wrong period. Which is why the Doctor refers to them as Homo repltilia, even though that’s not right either. Look, they’re intelligent reptiles who used to have a major civilisation which they sort of abandoned due to an astronomical miscalculation and have been in suspended animation for millions of years. Except when they occasionally wake up. Their previous appearances are in a DVD set which I’ve mentioned previously.
Anyway, on with the show. Things are going a wee bit wrong at a drilling project in a Welsh village. Odd vibrations, security screens blacking out, people being dragged into holes in the ground, that sort of thing.
But the Doctor doesn’t know about that. He’s taking Amy and Rory on a trip to Rio for sun, fun and err, whatever else comes to mind. He steps out of the TARDIS and shouts “Behold – Rio!”, only to find that in one of its odd bits of getting deliberately lost, the blue box has actually taken them to somewhere a little less sunny: a Welsh village, which by a curious coincidence is the one where the drilling project is going a bit wrong…
It all goes a bit more wrong when Amy is dragged into the earth, somebody appears to be drilling upwards and the traditional force field appears over the village.
It gets even wronger when the Doctor realises who must be doing the drilling, the power goes out (of course), a young boy is captured and his grandfather gets stung with a very long and very venomous tongue.
But the owner of the sting is captured and turns out to be what I’ll continue to call a Silurian. A different variety from the ones we’ve met before, but definitely related. Her name is Alaya, and like her relations that we’ve met previously, isn’t keen on the “apes” who are infesting her planet. The Doctor leaves her with Rory, the missing boy’s mother and the slightly poisoned grandfather. He goes with Nasreen, the drilling project leader to negotiate with the scaly guys downstairs. Before he can do any of the usual dematerialistion stuff, the TARDIS is dragged into the depths of the planet, where the Doctor and Nasreen find a slightly larger “Siluruan” base than expected. Rather than a small clan of maybe as dozen of them, they see a vast underground city: a complete civilisation.
That’s all very well, but Amy’s in trouble. A Silurian scientist is getting ready to dissect her..
And so to the second part of the story, which begins with a voice over. A Silurian talks about how peace was made, and how the Doctor achieved it at a great loss to himself…
Lots of running around and factional disagreements between Silurians follow as the Doctor tries to get negotiations going. This would be fine, but upstairs (so to speak), things have gone really wrong. Alaya has taunted Ambrose (the boy’s mother) into killing her, which makes a hostage exchange a bit tricky. It’s made even more tricky when Alaya’s sister wakes up a load more warriors ready for a bit of all-out war. It’s made even worse than that when Ambrose reveals that she’s set the drill to start up again, which will make a bit of a mess of the Silurian city.
A bit more work by the Doctor and the Silurian leader leads to a plan. The Doctor stops the drill, the Silurians will go back to sleep for a thousand years, in which time the humans might just manage to be ready to be ready to cooperate.
Everyone piles into the TARDIS so they can get to the surface and well away from the drilling base which is going to explode, but there’s another problem. The crack in space and time, as seen on Amy’s bedroom wall, and too many other places, has appeared again. Ignoring Amy and Rory’s pleas to hurry up and get into the TARDIS, the Doctor decides to reach into the crack and see if there’s anything in there. He grabs something, but at that moment, Alaya’s sister crawls into view. She should be either back in suspended animation or actually dead, but naturally, she’s done the last bit of vengeful crawling. Rory gets in the way and she shoots him.
Rory lies dying, and there’s nothing the Doctor can do – the energy from the crack is leaking out and if that touches you, you not only die, you cease to have ever existed….
He pulls Amy into the TARDIS and they leave, just as tendrils of energy envelop Rory. The Doctor tries to force Amy to remember Rory, but fails…
After dropping off the survivors in the village, the Doctor sends Amy back into the TARDIS while he finally examines the thing he pulled from the crack. It’s a burnt fragment of the sign on the front of the TARDIS.
Things are going to get a lot nastier…
Now that was interesting. The main Silurian story followed the traditional path up to a point – though with a more hopeful ending than any previous encounter. But the elimination of Rory was a bit of a surprise. And not just killing him, but erasing from ever having existed was an even bigger surprise. Is he really gone forever? Or will strange things happen in the weeks to come?
All I do know is that the series finale is going to be another Very Big One. And if I did know more than that, I wouldn’t tell you, so there. Oh, OK. I will let on one little non-secret detail: River Song will be back for the finale.
 I’m quite sure it does it deliberately
 I’m skipping a lot of detail here, of course.