The Season 10 Finale of ‘Doctor Who’ Welcomed Back an Original

The Doctor stumbles from the TARDIS grappling with his own regeneration, Missy comes face to face with her masculine past self, and the plucky Bill Potts gets turned into a horrifying cyberman. These are the three chilling cliffhangers “Doctor Who” left us with in the first half of the season finale, and kept fans all over the world hungry for the second helping of a pulse-pounding finale to the show’s 10th season.

There’s so much to unpack from this sometimes uplifting but mostly heart-breaking episode, from Bill (Pearl Mackie) coming to terms with her new cyber self to The Doctor (Peter Capaldi) scrambling to save the inhabitants of Floor 507 on a giant spaceship overrun by cybermen. But the most compelling story comes from, technically, the same character interacting with herself, with Missy (Michelle Gomez) and The Master (the returning John Simm) playing off of each other with such grace you’d think the pair had shared the screen for seasons. Missy’s new allegiance to The Doctor puts her at odds with her evil past self, leading to an episode full of Missy playing both sides of the coin — one second she’s on The Master’s side, willing to torture and kill The Doctor once and for all, and the next she’s knocking her past iteration loopy and coming to The Doctor’s aid. It’s refreshing to have Gomez finally able to project her wild personality at full tilt, her character having been trapped in a vault for most of this season.

The Master and Missy put their differences with The Doctor aside when the latter Time Lord re-programs the Cybermen to hunt humans and species with two hearts, meaning Missy and The Master are just as screwed as all the humans on Floor 507. There’s no escape for The Doctor, whose Tardis remains on the spaceship’s bridge. But Missy and The Master hatch a plan to replace a faulty de-materialization circuit on The Master’s Tardis and escape, totally ignoring an impassioned speech from The Doctor to “stand with me.” It’s really one of the more remarkable speeches in recent show history, and that’s saying something considering how fond this Doctor has been of oratory masterclasses.

Meanwhile, the episode fleshes out so much of Bill’s character through her transformation into cyberman, first through the horror on her face upon seeing her mechanical reflection to the rage that eventually helps her harness her cyber powers. Aside from a few moments where Bill appears as she actually is, viewers mostly see human Bill because, as The Doctor explains, her mind has not yet adjusted to her cyber self and thus her mind acts like a kind of perception filter. It’s a situation that makes for heartbreaking television, perhaps the most tragic way to write off a companion in the show’s five-decade history.

Heartbreak and dissension aside, the episode certainly packs all of the fighting and explosions viewers have come to expect from a Doctor Who season finale, with Bill and The Doctor working together to dispatch Cybermen. The Doctor realizes that the only way to save the people of Floor 507 is to evacuate them to another floor and blow 507 to pieces, taking the cybermen out as well as himself. It’s a chance the heroic alien is willing to take, tasking Nardole (Matt Lucas) with watching over everyone and protecting them should another cyberman invasion arise. It’s not a role Nardole relishes, but it’s one he ultimately shoulders with Doctor-like conviction.

While war rages on Floor 507, Missy and The Master nearly make their dastardly escape, but Missy has one last trick up her sleeve. That trick is a dagger, which she uses to stab her past self and initiate his regeneration process, leaving The Master stunned at his cunning future counterpart. Missy turns, set on returning to The Doctor’s aid and saving the day, but with his final effort, The Master blasts her with his sonic screwdriver. And so both Master iterations return to what they really are: cold-blooded killers.

With Floor 507 clear, The Doctor blows more Cybermen away, but he takes two full-force blasts in the process. The Doctor dies in a blaze of heroism, and one last cyberman advances on his prone body. It’s Bill, who kneels at his side and weeps for him. Heather (Stephanie Hyam) makes a miraculous return, restoring Bill to her human self, or perhaps something more than human. Bill and Heather manage to leave The Doctor in his Tardis before heading out to explore the universe together, but not before Bill cries one final tear that drops onto The Doctor’s face, giving him the life that he had lost, thus re-initiating his regeneration. It all comes full circle, going back to The Doctor’s mantra over the latest story arc: “Where there’s tears, there’s hope.”

Our final scene is also this story’s first: Consumed by his regenerative energy, The Doctor bolts from his Tardis, determined to fight the change that he knows is coming. “I can’t keep on being somebody else,” the Doctor bellows, digging his hands into the freezing snow to stop the energy from consuming him entirely. A figure emerges, proclaiming itself to be The Doctor, “the original, you might say,” ending the season on another steep cliffhanger. Set your Tardis controls to this year’s Christmas special, where Capaldi and show-runner Steven Moffat bid the show a proper farewell.

This episode was just drenched in goodbyes — from Bill and Heather venturing out on their own to Nardole staying behind to watch over the humans trapped on a spaceship to Missy and The Master both dying untimely deaths — making The Doctor’s staunch refusal to say his own goodbye particularly captivating. Although as River Song and Amy Pond found out, “The Doctor hates goodbyes.”

Doctor Who‘s” season 10 finale aired July 1 on BBC America. Season 10 can be viewed in its entirety on and on BBCA’s app for iPhone and Android.