Also, the minisode: Doctor Who: The Great Detective.
First, I want to address Matt and Jenna teasing us about who the new companion is and her connection, because quite frankly if we know anything by now is that her first appearance in "Asylum of the Daleks" wasn't a coincidence. Quite frankly, I don't believe that she really is Clara as she claims, or she may be "programmed" to believe that she is.
Secondly, it's interesting that the Doctor appears to have retired from his regular line of work. We know previously that he's been attempting to delete his name and existence from everywhere possible, especially from those who want him dead. But him retiring seems rather of a turn from who he is. He seems darker, more worn and exhausted, and possibly a little haunted. This season has been focusing on the Doctor showing his darker side more often. Some have speculated that this turn might be because of what happened to Amy and Rory, which might be a contributing factor. Although, wouldn't it have gone against Amy's wishes? She wanted him to continue being himself, but not be alone, because she knows him when he is traveling alone, and if nothing else I would think the Doctor would want to honor that at least for Amy's sake. This makes me think it's something else that finally drove him over the edge into retirement.
What is something happened to River? As in, what if the inevitably happened?
We don't know precisely when they visit the singing towers before he gives her his old sonic screwdriver and sends her back to where we know that is the last he'll see of her. From the last episode it's been revealed that she has been pardoned of all charges against her and that she is now a professor, so it's too close for comfort. Also, River is mostly associated with the Ponds, because she is their daughter, and with them gone it's inevitable that her end will come to pass as well. I don't want that too happen, not yet, but if the Doctor seems to be retired it's quite possible he is in a grieving mode because after everything, he doesn't have anyone. Not his friends he considered his family, not his wife, and everyone he has ever cared about has disappeared before his very eyes. So perhaps he knows that instead of traveling alone he has decided to press pause on everything. That is, until he encounters his new companion that motivates him to continue what he does best and find his sense of purpose again, which may or may not be connected to her particular origins as I'm hoping is the case.
Keep in mind all of this is purely speculative on my end. I have no idea what is in store or how it's all gonna play out, and how it's all connected to what we've seen thus far. I'm just crossing my fingers that the outcome is worthwhile and makes me anticipate the rest of the season. Regardless I'm already in love with Jenna Louise-Coleman and her adorable self, so there's that. ;) ♥