Jamie Mathieson, I love you.
Last season, he wrote both Flatline (with a very clever idea) and Mummy on the Orient Express (which, admittedly, has grown on me with repeated viewings). Mathieson has a really talent for sharply measured characters, clever inversions of ideas, and flat-out wit.
Even writing with Steven Moffatt, there's a charm and intelligence to Mathieson's work that makes The Girl Who Died - the first part of another two-parter (of sorts) - the highlight of Series 9 so far.
I say "of sorts" because The Girl Who Died could easily have been a done-in-one episode. Premise is simple: aliens are harvesting Vikings, a challenge is made, and the Doctor assembles a ragtag group of warriors, and shenanigans abound. But what really makes it work....well, it's several things.
First, Maisie Williams' performance. I'm not a Game of Thrones fan (the first three episodes bored me, and I'm tired of obnoxious fans telling me why I should watch the show), but she really sells the character of Ashildir, a young woman who is something of an oddball. (If there's one thing Doctor Who does well, it's provide some great off-kilter characters). Coupled with the writing, The Girl Who Died provides a nice tapestry of character moments.
Capaldi's Doctor realizing why he "chose" his face. Clara's increasingly Doctor-esque behavior. Moments involving the problems of immortality. It's a very heady brew, and a Doctor Who story that seems simple....but is incredibly complex.
And it's a "sort of" two-parter in that The Woman Who Lived is not a direct continuation - the cliffhanger is more of a "what's gonna happen next?" than a "How are they going to get out of this one?"
The first masterpiece of Series 9....and eager for more to come.