Something’s happening to Clara that we haven’t seen from her before: She doesn’t want to leave the TARDIS. Ever. The Doctor used to be a weekly note on her calendar; now, he’s the only note on every page of a calendar that she’s probably already thrown out the window. Her fight or flight response is all fight, all the time. It’s fitting, then, that the Doctor and Clara find themselves in a war this week, arguing over the virtues of dying in battle — and every question the Doctor asks about the townspeople is a question about Clara. Is there any way to win?
Fresh out of their latest space adventure, the Doctor and Clara make a pit stop in the age of the Vikings, who didn’t ask for company. They aren’t even impressed by wearable tech, snapping the sonic sunglasses in half and dragging their visitors back to the village in chains. (“Clara, we’re going with the Vikings.”) The Doctor is stopped in his tracks by the sight of a teenage girl named Ashildr (Maisie Williams, working an updo), who might not be a face from his past, but he’s pretty sure she will be someday. She welcomes the warriors like family.
The Doctor tries again to win his captors’ respect, but yo-yos just aren’t what they used to be. No one believes that he’s Odin (“Oh, and you would know how, exactly?”), and that’s before an actual face appears in the clouds, claiming to be Odin. He does look convincing — Viking helmet, metal eyepatch, clouds — but the Doctor isn’t buying this act any more than the villagers bought his. That’s the thing about the gods, he says: They never actually show up.
The Doctor isn’t big on false idols, and he’s worried that he’s become one for Clara, who jumps into action as soon as there’s trouble. Odin beams his army down to earth, where they hand-pick the Vikings’ best warriors and teleport them away. Clara tells Ashildr to put on the sonic sunglasses — or half of them, at least — and think “open” as hard as she can, so Odin’s army grabs them, too. The Vikings assume they’re in Valhalla, but it’s more like what would happen if Sweeney Todd designed a spaceship. A wall closes in, pushing them into a hallway that’s ready to vaporize everyone.
The Viking warriors are killed, but Odin spares Clara and Ashildr, just as Clara expected. She’s obviously not from around here, and Odin doesn’t want to risk starting a war that he can’t be sure he’ll win. Anyway, he’s juicing on the adrenaline and testosterone of a bunch of dead warriors, so he got what he came for here. Clara offers to let Odin leave (“The universe is full of testosterone. Trust me; it’s unbearable”), but Ashildr isn’t so willing to let this go. Her people are dead, and she wants someone to pay for it. Ashildr volunteers her village to fight 10 of Odin’s warriors, and he accepts her challenge as Clara wonders why she brought this girl in the first place.
Odin sends Clara and Ashildr back to the village to deliver his message — and, in Clara’s case, get a bear hug from the Doctor, who has news of his own: He’s been doing some research on their invaders. The Mire are one of the deadliest warrior races in the galaxy. He advises everyone to just hide out in the woods for a week and let this pass, but they’d rather die with honor, even though Clara is the only one among them who’s ever held a sword in the field of battle. (Details, please.) A baby cries nearby. “Do babies die with honor?” the Doctor asks. He says later that a good death is the best anyone can hope for, but this wouldn’t be a good one. Courage itself isn’t enough of an ideal.
But the village insists on fighting, and as much as the Doctor wants to leave everyone to die — a town capable of defeating the Mire could get this planet in bigger trouble — he can’t say no to that eloquent little baby. He’s the Shang to Ashildr’s Mulan. And it’s obvious that Ashildr is the key. She tells the Doctor that she’s always been different, and she believes in the power of the stories that she tells in her head. Sound familiar? When she mentions that the baby likes the fish in the boathouse, the Doctor remembers the child’s cries about “fire in the water” and realizes that the town has electric eels. Now he’s got it.
NEXT: Isn’t that wizard?
The village stays up all night to harness the Doctor’s new favorite thing: anachronisms (in this case, electricity and magnets). They electrocute the Mire, and a charge on the ceiling pulls off a few of their helmets. The Doctor fits one on Ashildr, who dreams up a story: A serpent is after the Mire. Not until his troops have all teleported to safety does Odin figure out that the “serpent” is actually just the bow of a boat fixed to a few wooden gears. Ashildr tapped into their visors and made them all see what she saw. The Doctor can either transmit footage of their embarrassing retreat to the galaxy, or the Mire can back off now. Odin chooses door No. 2.
But the Doctor couldn’t save everyone. Ashildr’s father finds her dead of heart failure, and the Doctor blames himself for treating her like a battery. He tells Clara that he’s sick of losing.
“I don’t mean the war. I’ll lose any war you like. I’m sick of losing people. Look at you, with your eyes and your never giving up and your anger and your kindness. And one day, the memory of that will hurt so much that I won’t be able to breathe, and I’ll do what I always do: I’ll get in my box and I’ll run and I’ll run, in case all the pain ever catches up. And every place I go, it will be there.”
The Doctor is so worried about Clara that he’s using other people as her stand-ins, judging his ability to protect his friend by his ability to protect everyone else. Which he can’t — or he can, technically, but he shouldn’t. Time travel has rules. This is starting to sound familiar. The Tenth Doctor had this exact argument with Donna in Pompeii. She wanted to avoid the tragedy, but it was Pompeii or the world. The Doctor remembers Donna’s compromise — “Just save someone” — and understands why he chose this face: “To remind me. To hold me to the mark. I’m the Doctor, and I save people.” Do it for Donna.
So the Doctor equips Ashildr with the battlefield medical kit from a Mire helmet, reprogrammed to work for humans, and she wakes up. It’s not until later that he lets himself consider the full implications of what he’s just done: The kit won’t ever stop repairing her. It’s possible that Ashildr has lost the ability to die. (“Dying is an ability; believe me.”) The Doctor knew that when he saved her — it’s why he gave her a second repair kit. He didn’t want to sentence her to an eternity alone. But he might still have created something bigger than he can control. “Winning is all about looking happier than the other guy,” and Ashildr doesn’t look too happy.