If you hung on until the credits had rolled on the latest Doctor Who special, Planet Of The Dead, then you'd have been treated to a 30 second taster for the next episode, whose title was revealed as The Waters Of Mars. If, however, you'd long since nipped into the kitchen to pop the kettle on, then allow us, through the miracles of, er, a bit of embedded YouTube video, to bring you up to speed on what you missed...