While Doctor Who is a sci-fi show that evolved out of something that was originally intended to be a science and history show, it’s always been at its strongest when it’s a character study. Just look at the difference between last week’s episode and this week’s. The Girl Who Died was largely a comedy episode. The Woman Who Lived was a study of Ashilder and the downside of immortality.

This week, it’s off the middle ages England where last week’s heroine is now a common thief. Hundreds of years of living and Ashilder may be a countess by day but is a masked bandit by night. I suppose hundreds of years of knowledge always seem to end in a life of crime.

The episode is really built around Ashilder coming to grips with the immortality granted by that Mire health kit device. It leads to some pretty good character development with Ashilder as we see the effects of immortality on a person and the obvious parallel with The Doctor.

Ashilder’s story is about coming to grips with the losses she’s suffered because she can’t help but outlive everyone she loves and the pain it causes her. It’s as if what she’s doing now is just as much filling the void as it is a way to get herself properly and permanently killed.

One thing that’s never really explored in Doctor Who is the long-term impact of losing his companions on The Doctor. Sure, Eleven gets a hallucinated Amy Pond just as he’s about to regenerate but there isn’t really any sort of permanent psychological effect that he has to overcome to operate normally again.

To draw a parallel with Law & Order, we saw how Claire Kincaid (Jill Hennessy’s Assistant DA character) whose death at the hands of drunk driver haunted Jack McCoy (Sam Waterston) to the point where he would prosecute drunk drivers with more fervor than he often have for prosecuting what most would call the worst criminals. Apart from maybe Ten in that Christmas episode where a follow-up is that he’d have let himself be killed stopping that spider thing if not for Donna, we haven’t really seen how loss of his companions has affected The Doctor.

I guess this is an examination of the morality of immortality. Is it wrong for Ashilder to throw her own morals to the side when the average lifespan is but a fleeting moment in her existence? Is it wrong to be forced to live when you are centuries removed from having anything to live for? Given The Doctor’s own near immortality and clinging to his own morality, it’s a sharp contradiction between the two even is Ashilder isn’t really a villain.

The theme of the season is coming together now and it makes me think that Moffat either knew that Jenna Coleman was leaving at the end of the season or he was planning to write her out. We keep coming back to people noticing how focused The Doctor is on protecting, saving and/or avenging Clara. While we thought that the big dark secret on The Doctor’s confession dial would be the crux of the season, it’s all about saving Clara.

When Ashilder talked about protecting Clara and asking how many companions The Doctor’s gone through, it all clicked for me. In each of the three stories this season, The Doctor has only sprung to action when Clara was in danger. When Clara was exterminated on Skaro, he sprang to action. When she was pegged as the next victim of the ghosts in the underwater base, he devised a plan and sacrificed someone to make his plan come together. And when the Viking village was pillaged, it was Clara’s abduction that got The Doctor off the sidelines.

I would assume that this theme will hold until The Doctor finds himself no longer capable of saving Clara. That’s the logical conclusion of this story. The Doctor has to make a mistake or he has to let his guard down or something along those lines at it has to cost him Clara. Not that this would break everyone’s heart.

Overall, I thought this was a good episode and certainly the best one since the Dalek two-parter to open the season. Even if it built off the pieces introduced in the last episode, like The Girl Who Died, The Woman Who Lives is a strong enough episode that it can work as a self-contained story without having to be propped up by plot development in a different hour of the show. It’s a strong piece of writing that can play off of an overarching plot while being strong enough to stand on its own.

Other random points of note:

• There’s the Captain Jack reference that we were looking for at the end of last week’s episode.
• Did no one think to come up with a plausible explanation of how Ashilder could make her voice sound like a man?
• Conspicuous by her absence: Jenna Coleman. Was she already off filming that new show of hers? It’s unusual to have a companion-lite episode unless we have a Doctor-lite episode being filmed at the same time.

Just when you thought it was safe on Earth, the Zygons are back to finish what they started in The Day of The Doctor. Remember when I said that they just dropped the whole storyline about the Zygons? Well, two years later, they’re back to clean that dangling plot thread up in The Zygon Invasion.

Cross-posted from et geekera. For more from et geekera, follow us on Facebook, Twitter, Google+, Tumblr, Steam and RSS.