In this week's episode, we end up in the time of the Vikings where the Doctor tries to convince them that he is Odin. The re-appearance of the yo-yo is a nice touch, and seems to be in reference to it being magic, rather than testing gravity. Odin appears in the sky, turning out to really be the leader of the Mire. Ashildr, played by Arya Stark ... sorry, Maisie Williams, acts emotionally, challenging Fake-Odin to a fight.
After discovering her love of telling stories, the Doctor uses Ashildr's imagination to save her village, but at the cost of her life. It as at this point that Capaldi sees his face in the water and admits he chose this face as a reminder that Donna had begged him to save anyone. As we expected, the Doctor has now decided it is his calling to save at least one person during each significant adventure. This time around, It's Ashildr. The Doctor modifies a computer chip from a Mire helmet and implants it on Ashildr, making her an immortal hybrid.
In terms of story, the writers seem to be hell bent on making sure we know exactly who Ashildr is, which means not much else happened. We can only hope that Williams becomes a recurring character from this point. She is a fantastic addition to this season's already stellar performances. Ashildr and Missy are shaping up to be up there on my list of favourite characters.
Other than the yo-yo, there are several other whovian delights such as the Doctor's 2000 year diary, the first we've seen since the 900 year diary. We are also reminded that the Doctor can speak baby, stirring memories of Stormageddon; Dark Lord of All. Capaldi has really stamped his name in Doctor Who Lights this series and I'm finally enjoying it as much as I used to. Even Clara is becoming bearable. (Yes I said it.) And yes, perhaps the Sonic Sunglasses aren't all bad, but is this the end? RIP Rayban?