Doctor Who: The Waters of Mars

Well, it was good. Actually, more than that. It was gripping. From start to finish. Just so much better than Planet of the Dead, which frankly looks lacklustre compared to last night's episode. Was it perfect? No. Any programme that contains a robot called GADGET is going to get on my nerves slightly. But that is a minor complaint when you consider just how much the show got right.

Firstly, it managed to be both tense and terrifying. In fact, much of the episode reminded me of various zombie films. The make-up of the creatures, combined with their creepy voices, reminded me of The Evil Dead, whilst the spasmodic, twitching that the victims did when they changed, combined with the single drop of water falling into a man's eye causing his death, reminded me of 28 Days Later. And when you consider that this series is a family show being broadcast on a Sunday evening, those are some pretty intense references to have. I'm not sure what children would have made of The Waters of Mars, but I know that had I watched as a kid, I'd be having nightmares for weeks afterwards.

It also contained neat references to other elements of Doctor Who without being obtrusive. In particular, I liked the idea that the Ice Warriors had frozen something in the glacier; something so monstrous that they felt encasing it in ice was the best way to deal with it. But it wasn't just the in-jokes and geek references that made it work. The episode also managed to feel like the logical conclusion of the Doctor being the last Time Lord. He was now able to write the laws of time, and turn himself into the Time Lord Victorious. And there have been few images as terrifying in Doctor Who than the hero turning himself into a meglomaniac. And the most challenging thing of all to take in was the fact that there was nothing wrong with what the Doctor wanted to do. He wanted to save lives, just as he does all the time, but he was forced by the laws of a long dead race to leave the pioneers of Mars to die in fear in Bowie Base One.

Which is what the heart of this outstanding episode was about. It showed two transitions - as the Doctor moved from being totally defeatist to being convinced he could change this fixed point in history, whist Adelaide went the other way. The darkness at the heart of The Waters of Mars was about how powerless all the characters actually were. The Doctor tried to break every rule to ensure Adelaide's survival, but in the end, she understood that she had to die. And has there ever been such a bleak end for someone who was effectively the Doctor's companion? She took her own life; effectively forced into it by the Doctor's actions.

It will be very interesting to see where they take the Tenth Doctor in his final two episodes. A number of options present themselves, and I would be staggered if the Doctor's drift into megalomania didn't have serious consequences for him. In fact, I wouldn't be surprised if the Doctor's actions here don't play a major role in what kills his tenth incarnation.

So, all in all, a fantastic episode. And a bittersweet one, because it shows - amongst other things - that RTD has finally worked out how to write brilliant Doctor Who just as he is about to leave the show. The script for The Waters of Mars was terrifying, though-provoking and brought out the very best in his actors. Whereas for so much of his time as a writer for Doctor Who, RTD's stories have been far more lightweight than what he managed to produce last year with Midnight and last night with The Waters of Mars.