Very minor visual spoilers ahead.
I am not kidding. This is the most intense Doctor Who episode ever. I had to take a break at one point. Steven Moffat outdid himself, bringing together all the threads into a masterful finale. Moffat is the master of space and time.
Hurran’s direction was terrific. He was inspired.
And there’s a promo for the Christmas special, with two shots from it — that I’m not showing:
Some day I want to write a Doctor Who script that has Moffat as a character writing this Doctor Who script.