Ten 'Waters of Mars' teasers

1. The first line of the episode: "Hello mum. Susie says hello!" Do not underestimate its relevance!

2. The Doctor (and TARDIS) land on Mars on November 21, 2059. There he happens upon Bowie Base One, the first human colony on the red planet.

3. Heading up the base is Captain Adelaide Brooke (Lindsay Duncan), recognised by The Doctor as the pioneer of humanity's colonisation of space. "The woman with starlight in her soul," he calls her.

4. Odd-Doctor behaviour part one: The Doctor instantly realises he needs to leave. "Whatever has started here, I can't see it to the end," he tells them. "I can't."

5. ... but he doesn't leave, because before too long the dreaded 'water' starts to play a part. We won't spoil exactly how it plays a part, but the previously-released preview clip offers a strong hint.

6. There are references to two season four stories, as well as the recent Easter special. There's even a (new) flashback scene to one of the aforementioned.

7. "It's taken me all these years to realise *** **** ** **** *** **** - and they **** **** **."

8. An Ood makes an appearance. Last word is key.

9. Did you know, the human body is 60% water?

10. Odd-Doctor behaviour part two: Towards the very end of the episode, there's a scene that sees The Doctor say things that will utterly shock you. And more than that, the way he says things will shock you too.