As usual spoilers can be found below.
Somehow events conspire so that the Doctor and Clara take Coal Hill schoolgirl Courtney on a trip to the Moon in 2049. The Tardis materialises on board a shuttle that then makes a crash landing on the lunar surface. On board the shuttle are three astronauts and 100 nuclear bombs.
The Doctor realises that the Moon’s gravity is too high, therefore the Moon must have gained mass. He is correct. The higher gravity is causing serious problems back on Earth and the astronauts have been sent to “kill” whatever is causing the problem.
We learn that mankind has more or less abandoned space travel by 2049. This mission was only possible because the last space shuttle had been taken out of a museum. Incidentally the visual effects do show an actual NASA-style space shuttle with a fairly effective crash-landing sequence. Also the makers have shelled out cash on some new spacesuits for the shuttle astronauts while the Doctor and his chums wear the usual red spacesuits that I think were first seen in The Satan Pit back in the David Tennant days.
And before I go on I do have to remark on the fairly impressive depection of the lunar surface. For a show made on a BBC budget it was very well done.
Eventually the Doctor realises that the Moon is not a planetoid but an egg (really), and whatever giant life form is inside is about to hatch. Clara is unconcerned. Surely, she reasons, the Doctor knows that the moon is still there in the future. But the Doctor is not so sure. He says sometimes there are grey areas, “eye-blinks” that stop him seeing what happens. He doesn’t know what is going to happen now. So there is a dilemma: should they kill this unique creature to guarantee Earth’s survival.
And then the doctor leaves Clara to make the decision.
Yes, he just leaves. This is where your mileage may vary. Surely the Doctor would stay to solve the problem as he always does? Or is letting Clara/the human race make the decision without his hand-holding the right think to do?
Clara is convinced that the creature should live. She sends a message to Earth telling people to choose by either turning their lights on for the creature to live or turing them off for the creature to die. She watches Earth through binoculars and the lights gradually go off. It’s a very effective sequence and it reminded me of a novel written by Stephen Baxter and Arthur C Clarke where an AI needed humanity to make a decision and says it will monitor the discussions on the internet to calculate what consensus mankind reaches.
Also this dilemma is very reminiscent of the second episode featuring Matt Smith, The Beast Below. There Starship UK was using a captured space whale as an engine and the citizens had to vote on keeping it captive. (Actually at one point I thought the creature might have turned out to be a space whale which would have been a nice nod to continuity, although it would have then reminded viewers of recycling of plots…)
So humanity makes it’s decision and Clara promptly, er, ignores it, stopping the nuclear bombs from going off. Just then the Tardis returns and the Doctor takes the survivors to Earth to see the creature hatch. The moon-eggshell dissipates and the creature departs, but not before laying a new moon-egg to sort out all that pesky continuity malarkey.
But the episode is not over yet. Along comes the most dramatic character-driven scene of the series so far. Clara lays into the Doctor big time. She’s furious that he would leave her there to make the decision on her own. The Doctor maintains it was a decision for humanity but that cuts no ice with Clara who tells him to leave and not to come back. Brilliant bit of acting from Jenna Coleman.
The episode is not without some problems. Chief among them is the small matter of the moon just gaining mass. Ok, there’s a creature inside growing, but how is it gaining mass? Is it eating? Eating what? This is such a basic plot point that they only way the writers can address it is to totally ignore it. I appreciate that you don’t watch Doctor Who for scientific accuracy but there should be at least some attempt to address such problems, even if it is just by adding a line to say the creature has a wormhole for a stomach that is sucking in matter from Jupiter. Or something.
(Speaking of wormholes, Stargate SG-1 always made an effort to put a bit of real science into how the Stargates worked. They did a good episode with time dilation one time… But I digress…)
Also, the moon is an egg? There’s a line of dialog that an earlier expedition of Mexican astronauts were looking for minerals but didn’t find any. Well, what about the rocks that the Apollo astronauts brought back? Sometimes it’s as if Doctor Who just exists in it’s own continuity separate from our own and I guess this is the case here.
And the central plot point of the episode: the Doctor leaving Clara by herself to make the decision. As I said, your milage will vary as it if this in character for the Doctor or not. But the gods of the script decided it was what he would do to advance their story so it happened.
In summary if you can ignore the lack of science and accept the Moon is an egg and the Doctor behaving out of character then it’s a fine episode that shows off an impressive Jenna Coleman playing an impressive Clara. The scene where she tells the Doctor to go is a real shock and the dramatic highlight of the series so far. Jenna totally sells it.