‘Fear is temporary. Love is slavery.’ Extremis could have been a mid-season tease for an end-of-series finale, but Moffat plunges directly into the follow up as the Monks’ plan for global dominion comes to fruition in a pyramid that has mysteriously appeared at the fracture point between the USA, China and Russia. At exactly the same moment, a biological research laboratory in Yorkshire accidentally threatens to wipe out all life. This series of unfortunate events has pushed the Doomsday Clock towards midnight – and only an appeal to the Monks can stop the countdown.

I’m not a great fan of Peter Harness’s previous Doctor Who scripts, which seemed to accidentally stumble into ill-thought-through pro-life and Islamist parables. I was on my guard when this opens like The Zygon Invasion, Part Three with the return of Arabistan (sorry, ‘Turmezistan’) and the Doctor’s presidential aeroplane conveying him and the UN secretary general (nice to see some proper UN blue berets again) to the pyramid. There is some overlap in the themes, with the idea of ‘consent’ bringing memories of the Earth being asked to vote on the Moon-dragon’s abortion, and ISIS and the UK military having to choose ‘Truth or Consequences’. But this thankfully avoids any unintended analogies (well, apart from the connotations of a woman being coerced into ‘consent’ to invade the borders of her realm).

Instead, it’s the Doctor’s (very Moffatian) monologue at the top of the episode that gives the story its impetus: ‘The end of your life has already begun… and every step you ever take is moving you closer.’ Here, inexorably, humankind wanders towards its own destruction as research scientist Erica breaks her specs on the very day her colleague Douglas has come into work hungover. These innocuous accidents lead Douglas to mix his enzymes incorrectly, condemning his species to death. The great and powerful gathered at the pyramid are almost irrelevant – the world doesn’t die due to an itchy trigger finger, but because someone got their sums wrong.

Luckily, humankind has got the Doctor – who races to the lab and fixes the problem. Except, he’s blind and (thanks to the usual contrivances – see also Rose’s dodgy lever and Clara’s tattoo) has got himself locked in with a bomb. And so, Bill sacrifices the world to save his sight. I remain a bit torn on this: it’s perfectly possible I’m being overly sensitive, but I did find it a bit ick that the Doctor’s disability is the reason he’s not as good as he used to be, and the cliffhanger playing so heavily into the trade-off Bill makes to cure him: ‘Enjoy your sight, Doctor. Now see our world.’

So far, I’m deeply ambivalent about this storyline. The Monks look creepy, but aren’t very interesting, and the blindness plot has boiled down to making the Doctor weak so they can win. In the end, we’ve had two episodes of set up for an alien invasion. That’s twice what we’ve previously had for the Daleks or the Cybermen, so I can only hope the pay-off is twice as good as Death in Heaven or Doomsday.

Next Time: The Lie of the Land