“Dark Water” is episode eleven of season eight of the new Doctor Who and the first of the two-part season finale.
As might have been guessed from the not-so-subtle hints (Bad Wolf and Torchwood were subtle; these were not) throughout the series, the season finale involves Missy. Who seems to deal with dead people. So, you’re going to need a dead person.
Clara is talking to Mr Pink on the phone and, just as he is getting the phone, it all goes quiet. You can guess what happened. In fact, you could practically see it coming. Might have worked better if they’d done a better job of making us like Mr Pink. So, what do you do in this situation if you know a guy with a time machine? Well, that sort of thing doesn’t work so well, as Rose proved in “Father’s Day” when she saved her father. So, a different method is needed, which involves physically finding Danny using the TARDIS. He’s in somewhere called the Nethersphere.
At one point, the Doctor says that he thinks he is missing something obvious. And there is promptly a clue as to what he is missing. In fact, there are two old ‘friends’ to contend with.
Despite the subject matter, there is quite a lot of humour in this episode. The story continues in “Death in Heaven”.