The Doctor has been persuaded to take Clara’s charges Angie and Artie on a trip to what’s supposed to be the galaxy’s biggest and best theme park, which in the usual sort of way, turns out to have been closed down long ago, and only occupied by Webley, a man who’s sort of running what’s left of it and Porridge, who’s hanging around for reasons of his own. Oh, and there’s a moderately rubbish group of soldiers.
There’s also a hollowed-out old Cyberman, set up as a Mechanical Turk with Porridge (played by Warwick Davis) hiding inside.
But that wouldn’t be much fun, would it? So there are also some tiny machines, which the Doctor describes as “Cybermites” – rather like the Cybermats we know and err, know of old, but smaller and more sophisticated. And they are soon followed by a huge army of Cybermen. But these aren’t the lumbering giants of old. They’ve been upgraded a wee bit. They now move very quickly – so fast that you won’t see them coming. And they can upgrade their defences on the fly, so if you’ve got a fancy Cyberman-defeating weapon, don’t count on it working for long…
The real fun bit starts when Cybermites infect the Doctor and he becomes partly converted, leading to a lovely performance from Matt Smith as he switches between personalities, argues with himself and has a discussion with himself inside his mind.
Secrets are revealed (but nothing to what’s coming), fun is had, and Neil Gaiman pretty much pulled off the feat of making the Cybermen a much more real and scary threat.
Coming up next week, the series finale, where we will allegedly get to know a lot more about Clara, and even more about the Doctor. Oh, and an appearance from River Song, too.
 That’s the original chess-playing fake automaton, not any Amazon thingy