'If the moon breaks up it'll kill us all in 45 minutes.'

Can it be saved? asks Lundvik, a desperate astronaut.

'Depends what's killing it,' replies the cool Doctor.

The episode opens with tension. A frightened Clara looks into the camera saying, 'we have a terrible decision to make and we don't have a lot of time!' but there was still room for little flickers of comedy throughout.

Maybe all the episodes have this mixture but readers of this column will be aware I'm new to Doctor Who. I've only seen three episodes: the awful Deep Breath, the magnificent Listen and now this one, Kill The Moon.

After the tense opening scene, we flashback. The Doctor is in the Tardis being nagged by two women. An annoying London schoolgirl, Courtney, is whining 'don't you fink I'm special?' whilst Clara badgers him to be nice.

Stuck with these hen-peckers, Peter Capaldi turns to the brat and with growling gallantry, transforming him into a magnificent Glasgow Heathcliff, asks: 'How'd you like to be the first woman on the moon? Is that special enough for you?'

They crash land on the moon to find nuclear bombs and some very grumpy astronauts. The Doctor jumps and twirls and skips in front of them. An embarrassed Clara asks what he's doing. 'There's no gravity,' he says. 'We should be bouncing about this cabin like fluffy little clouds but we're not.' He turns to face the astronauts: 'What is the matter with the moon?'

It's clear something is terribly wrong. It is cracking and shifting, putting mankind at risk. The Doctor says, 'it must be causing chaos on Earth. The tides will be so high they will drown whole cities.'

The trio of grim-faced astronauts have been sent here to fix it and, of course, are approaching the problem as humans do: with bombs. A hundred nuclear bombs lie stacked and waiting, but first they need to discover what the problem is. What is wrong with the moon?

When the group step onto the lunar surface to investigate they're faced, not with terrorists or aliens, but cobwebs. Rocks and caverns are choked with thick, dusty webs, as are the skeletons of astronauts who'd been here previously.

This was a very eerie part of the show, with the group making their way across the grey, silent surface, knowing only that something is wrong and that it involves some very hefty spiders. With the barren landscape, lack of atmosphere, and bleak, empty horizons we're reminded the show is made in Wales - though this segment was filmed on volcanic Lanzarote.

The tension rockets when the group re-enter the spaceship and hear the dreadful ticky-ticky-tick of a massive spider skittering over the metal floor. These ones are just as terrifying as your average British house spider, being huge, aggressive and studded with red lights. 'It's the size of a badger!' says the Doctor. And there are millions of them on the moon, 'multiplying, feeding, evolving…'

The Doctor discovers that the spiders are merely bacteria. They're not what's wrong with the moon; it's what the bacteria are feeding on that's the problem.

When we finally discover the alien who's destroying the moon, the astronaut, Lundvik, says simply: 'Doctor, how do we kill it?'

At this point, the plot began to weaken. Until now it'd been a great story, full of tension, surprise and good old-fashioned scares, but when we finally discover who the 'baddie' is, and with Lundvik ready to blast it, Clara and Courtney lapse into faux philosophy and daft moralising. Is it right to kill this thing, they wonder. 'This is a life!' says Clara.

Lundvik can hardly believe these two daft girls. If this alien is allowed to live humanity could perish. What about life on Earth?

'There's life here, too!' they plead. It'd be so sad to kill a poor little alien…

'Things don't always have to be nice!' snaps Lundvik. Maybe I'm heartless, but I agreed with her and had no tender feelings towards the alien. Clara and Courtney talked as though it was the agony of deciding on an abortion.

This was such a fake dilemma: a choice between killing an alien or saving the human race. But perhaps I'm a Texan at heart, because I felt just like George W Bush, shouting: 'Just bomb the thing! Nuke it! Shock and awe! Bring our boys home!'

'We have a terrible decision to make' weeps Clara. 'We don't know if it will help us or hurt us or just leave us alone.' Should they blast it with nukes or let it live and perhaps destroy Earth? Shock and awe, baby! That was my answer.

Kill The Moon was a good story: eerie, tense and clever, but it was padded out with too much of this fake moralising which soon became tedious. As they discussed whether to save an alien or save humanity it felt like a multiple choice quiz from a magazine called Do Gooders Weekly. If you chose Option A, Saving The Alien, then you'll go to heaven. If you chose Option B, Nuke That Bad Boy, then you'll go to hell.

This episode may have made me feel unnervingly like Dubya but at least it was far superior to the awful opening episode and the series seems to be getting better all the time. I might be inching towards watching Doctor Who regularly. Shock and awe!