While I’m not planning to go into a lot of plot details, it’s likely that the random mutterings that follow will reveal some things you might prefer not to know if you haven’t seen the episode yet, so in my usual way, I’ll include this warning:
Oooooooookaaaaay. Now this was a seriously good episode. Don’t get me wrong, I’ve enjoyed every one so far this year, but this one turned the knobs up to some arbitrary number you don’t usually find on knobs and then got better.
Just for a change, the Doctor was trapped, and Clara had to do most of the fun stuff – including the psychic paper and sonic screwdriver bits, leading her to ask the Doctor if that meant that she was him…
The threat this time wasn’t a malfunctioning machine or a soldier still obeying old orders, it was a proper actual and nasty threat. And making invaders from Flatland into an actual nasty threat was very nicely done, with walls becoming dangerous, doors becoming nothing at all, and fun with trains. Real trains this time rather than space trains, though.
We also had some serious Tardis abuse, with its outer shell being reduced to a nicely portable size, and it being established that the real weight of the ship is always altogether elsewhere. It’s also established that a Tardis in low power lockdown mode presents itself as a tasteful cube with Gallifreyan markings. Good to know.
And that’s all I want to say – any more might spoil the fun for hypothetical readers who haven’t seen it yet.
If you have seen it, make sure to watch the spoiler-heavy Doctor Who Extra: