Warning: Major character death at the end of this. Please note that this was written for a combined audience of Whovians and people who've barely ever heard of the show, so I had to explain some things. I worked it into the story as best I could, but if there are any overly long descriptions, that's why. This is also posted on AO3 under the same username.

Disclaimer: I don't own Doctor Who.

My name is Clara Oswald, and I am the Impossible Girl. I travelled through time and space with the Doctor in his TARDIS, and saw things you could never imagine. I sacrificed myself to save him, entering his timeline and fracturing myself into a million people, all throughout history. And all throughout time, I was always running, always will be running, to save the Doctor.

No one can survive entering another's time stream, but the Doctor has never been one for endings. He saved me, and I lived. The Impossible Girl.

I was with him when he regenerated, and in time, I learned to trust the new man he became. I ran away with him. And everything was as it should be. Clara Oswald, with the Doctor, in the TARDIS. Running. Running forever, because he can never ever stop.

Until one day I flew too close to the sun. A friend of mine was framed by Ashildr, a girl that the Doctor had saved and cursed to immortality. The Time Lords forced her to do it, to lure the Doctor into a trap. She didn't want anyone to get hurt—she had already made a deal with the Quantum Shade, the raven, her executioner.

Only she took me under her protection, promised that no harm would come to me. So, I convinced Rigsby to give me the tattoo to buy us time. Ashildr's bargain with The Raven that she could remove the tattoo from Rigsby. But not from me.

On November 21st, 2017, I stood in the street as the Quantum Shade flew towards my chest, a smoky black raven that would be my death. "Let me be brave," I whispered, and then I died. My story was over.

But the Doctor has never been one for endings. He forced the Time Lords to extract me from my timeline, frozen between one heartbeat and the next. He ran away with me, but we were too dangerous to stay together. I reversed the polarity of his neural blocker rather than let him erase my memories, and he didn't believe me. The Doctor was the one who lost his memory. Lost his memory of me.

I stole a TARDIS and ran away. Ran away with Ashildr from the mess that I had made with the Doctor. "Where are we going?" Ashildr asked.

"Gallifrey," I told her. Because I wasn't even alive. No matter what, I die. But I had become like the Doctor. And I had learned from him. One day, I would return to my timestream and face the raven. But until then, I could run. "Like I said, Gallifrey."

"The long way around."

The room was white, sterile. Everything about it was perfectly even, down to the roundels on the walls. One side of the room was taken up by panels with rectangular lights, lined up in neat little rows. The TARDIS console sat near the center of the room, filled with blinking lights and various artronometers and radiometers and other -ometers that Clara really didn't care to memorize the names of.

"So," said Ashildr—or Me, as she preferred to be called— "where to next?"

Clara closed her eyes, thinking. "We can't keep running forever," she said, leaning on the console to watch Me's reaction.

"And no one can live forever," Me said, raising an eyebrow. "You're the Impossible Girl. You can do anything you want."

"But there you are," Clara said. "No one can live forever." Unconsciously, she pressed two fingers against her wrist to check her pulse. As always, there was nothing. She wasn't even certain that she remembered what it felt like, to have her heart pumping blood through her body, to be truly alive.

Me rolled her eyes. "You think you've lived for a while," Me said. "Believe me, you haven't. I've reached the end of the world the long way around, and I'm still here."

Clara shook her head. "I'm not even alive," she reminded her. "Frozen between one heartbeat and the next. Because the Doctor couldn't just let me die."

"Daleks," Me said. "At 9-33-27-0-3/5-9. Burning up a planet. We could save them, if you want."

"And you don't want to," Clara guessed.

Me shrugged. "What's the point? Those people will die anyway in a few years. But we could go. Play hero. They'll sing songs about us and we'll become legends. Is that what you want?"

"What I want," Clara said, frustrated, "is to be travelling with the Doctor. And no, it's not your fault, so don't even try that."

"Clom. The forests of Cheem. Padrivole Regency 9. Voga. Neogorgon. Anywhere in the universe. See anything, do anything," Me said, circling the console with one hand trailing on the cold white surface.

"Earth," Clara said quietly. "I want to go to Earth. 2017."

Me shrugged with one shoulder. "Fine with me." Clara pulled a lever, setting the galactic coordinates with a dial, a few buttons, and a switch. Me took care of the temporal coordinates, flying around the console. Clara listened to the sound of the TARDIS phasing in and out. Technically, that sound was what happened when the brakes were left on, but it reminded Clara of the Doctor. He would call it the most wonderful sound in the world.

Not that she could even remember what he really looked like anymore, or what he sounded like. Human brains simply weren't designed to last centuries, and like Me, she didn't have enough space for her memories. Now, the most she could remember of her childhood was her mother, and even that had faded away over the years. After spending over six hundred years travelling with Me in the stolen TARDIS, Clara had forgotten almost as much about the Doctor as he had been forced to forget about her.

"Here we are," Me said. A hatch opened in the paneling of their TARDIS, revealing a hidden compartment. Me removed two guns from it. She handed one to Clara, and began to walk towards the door.

"Most humans don't exactly go around carrying large guns in their hands. We won't exactly be inconspicuous."

Me rolled her eyes. "Immortals can die too, you know, if you kill them right." She would know—at the end of time, there had been only one person left. Just Me. Somehow, Me had outlasted all of the other immortals.

"Twenty-first century Earth," Clara said. "No one's going to be killing anybody."

"Isn't this where you come from?" Me asked. "Crossing your own timestream…that's dangerous."

"What's life without a bit of risk?" Clara said.

"That's what got you killed," Me reminded her. "Taking stupid risks."

"Oi! Not dead yet!"

"They have a low-grade perception filter," Me said. "No one will notice a thing."

"The Doctor didn't like guns," Clara remembered suddenly. "I should write that down, somewhere." She had given up recording her memories about fifty years ago, but she still occasionally wrote notes to herself on a whim.

"You can when we get back. Come on." Me shook her head. "Twenty-first century Earth. Of all of time and space, twenty-first century Earth."

Clara shrugged, opening the door. "That's where I'm from." She stepped out of the TARDIS, Me close behind her. And then she looked out.

Wherever they were, it definitely wasn't twenty-first century Earth. This was fairly obvious, with the giant spaceship in the sky and the people carrying giant guns. They shouted, firing into the smoke that surrounding the whole scene. A shot of red energy flew right past their heads, just barely missing the TARDIS, which had taken the form of a large grey rock to blend into the surroundings. Clara pulled the TARDIS key necklace that she wore off her neck, trying to insert the key into the lock, but fumbling. The TARDIS began to phase out.

"C'mon, c'mon, c'mon!" Clara said. She turned, but her hands slipped, and the TARDIS disappeared, taking the key with it. "I told you!" She yelled. "Don't turn the emergency relocation back on!"

"Well, I didn't think this would happen," Me protested "It can't have left the planet, just…gone somewhere safer. Let's see what all the fuss is about." Another shot missed them by inches, and then out of the smoke came an army.

Their metal skin was bright and clean, untouched by the war around them. Their heads were square-like, with large circular holes for eyes and a thin line for a mouth. Above their forehead shined a blue light, the same as the circular bulb in their chests. The soldiers marched in perfectly strait formations, not a millimeter off, heads fixed on the enemy in front of them. Metal feet stomped in unison on the hard dirt ground, sending a flurry of dust into the air, already thick with smoke. Attached to their arms were guns, shining through the battlefield, firing off into the distance.

Clara could hear the soldiers marching all around her, a thousand deadly knights in battle. But these were not knights.

These were—

"Cybermen," Clara whispered. "Me, if—"

"I don't know," Me interrupted. "Cyberconversion might stick for me." Clara spun around to see a Cyberman standing ten or so feet away from them. Its gun was pointed straight at the two women. Me fired at it, five times in quick succession, but the red energy blasts bounced harmlessly off the creature, forcing Clara and Me to duck.

"YOU ARE COMPATIBLE," the Cyberman said, facing Clara. "YOU WILL BE UPGRADED."

Clara grabbed Me's hand. "Basically—"

"Run!" Me finished for her, as the two ran off into the smoke, the Cyberman firing after them.

Everywhere Clara and Me turned, there seemed to be Cybermen, their guns releasing blue energy as they marched in formation. A troop of Cybermen emerged from nowhere. Me shot at them desperately, but the energy blast ricocheted off the soldiers, forcing Clara to pull Me to the ground. Clara ducked her head, waiting for the energy to pass. Just because she couldn't die didn't mean it wouldn't hurt.

When Clara finally looked up, the Cyberman had closed in a circle around them. Where is the TARDIS? Clara wondered. If it relocated somewhere safe…where is safe when the Cybermen are destroying the planet? Are we even on Earth?

"YOU ARE CLARA OSWALD," said one of the Cybermen in its cold, mechanical voice. Its eyes were empty holes, and Clara couldn't see anything behind them. Somewhere in there was a human brain, devoid of all emotion. This monster had been a person once, a scared person whom the Cybermen had taken captive and stripped the humanity from, until it was a shadow. A mindless robot with 'biological components'. No wonder the Doctor hated soldiers.

"Yes, I am," Clara said. She could try to convince them that she was the Doctor again, but what was the point? They hadn't believed her the first time around. What had happened the first time around? Clara had met the Cybermen before, she was sure of that. Multiple times. Chess and volcanos and a strange woman twirling around like a demented Mary Poppins. Someone had died. Someone very important had died, and she couldn't remember who it was. "What're you going to do about that?"

One of the Cybermen grasped Me's arm, squeezing it so tight that Clara could hear the bones crunching. Me gasped in pain. "YOU ARE NOT COMPATIBLE," it told her. "YOU WILL BE DELETED." Blue energy crackled around the Cyberman's arm, leaping onto Me and causing her to scream in pain. Mire, Clara remembered as she stared in shock, her gun useless against the Cybermen. She's part Mire, she isn't fully human anymore. Cybermen can't convert her. Me slumped onto the ground, and Clara turned back to the Cybermen.

"DELETION WAS SUCCESSFUL," one of the Cybermen announced. Then, it spoke to Clara. "YOU WILL COME."

"Er…no I won't," Clara said, standing up and holding her gun. Any second now, Me's body would begin healing her, bringing her back to life. The Cybermen would realize, and come up with a better way to kill her. Or worse, continue trying to electrocute or shoot her. Which meant Clara had to get them away from Me. She scanned the circle of Cybermen, considering her options. There weren't any gaps large enough for her to run through—she was trapped.

"YOU WILL COME," the Cyberman repeated. "CLARA OSWALD WILL BE BROUGHT TO CYBERCONTROL." Clara squinted at them. Alright, she thought. The Doctor would say that the best way to find out the enemy's plan is to get captured, right? I think that's what he would say. Clara shrugged. They couldn't kill her—she wasn't exactly alive. And even a Cyberconversion would degrade, according to Me's calculations, although Clara wasn't certain if the mental effects would stay. Her death was a fixed point in time; she look exactly like she had when she returned to Trap Street.

"Okay," she said, holding up her hands. "I'll come." Two Cyberman grabbed her shoulders, one on either side. "You don't need to do that," she complained. "I said, I'm coming." They didn't listen, marching her through the smokey field.

Around her, Clara could hear screaming and explosions. "Rosa!" Someone screamed, their voice raw. "Rosa! Rosa! Where are you? Please! Rosa! Ro—" He stopped, abruptly, as another explosion sounded. Clara winced. It got easier, watching others die, but she was never able to completely ignore it.

Clara felt her pulse again, a nervous habit. Like always, there was nothing. Clara was a living ghost, an impossible girl whose time was up but kept on going. I wonder how we ended up here, of all places. It's certainly not Earth, and it's certainly not 2017.

The Cybermen stopped marching as they reached a large disk in the ground. All of them crowded on, squeezing Clara into the center. Then, in a burst of light, the world around them disappeared.

Clara blinked, clearing the blurriness from her eyes. Dizzily, she looked around, observing that she was now in a large room. The walls, the floor, and the ceiling were all cold grey metal, without a single decorative element. "So," Clara said, looking around. "Nice place you've got here." The Cybermen didn't seem remotely interested in discussing interior design. "Where are you taking me?" Still no response. They marched until they reached a large door, which slid away to reveal a giant room.

When Clara thought giant, she meant giant. Around her were thousands of Cybermen, lined up in orderly rows and facing towards the front of the room. Their polished metal gleamed in the light from the blue spheres that hung around the ceiling. They had cleared a path to the front of the room, where the Cybercontroller sat. It had its brains revealed, heaping out of the top of its head, and it gleamed silver. Blue spheres hung around it, sending bolts of energy into the blue circle on its chest. The large door shut behind her, cutting off her only exit.

Clara stepped forwards tentatively. The Cybermen stayed guarding the door, so she stepped forwards again. The room was silent, except for the steady hum of machinery. And then, the Cybercontroller spoke.

If the Cybermen normally sounded frightening, then this was a voice that would strike terror into the hearts of Daleks, if Daleks could feel afraid. It was cold and clear, screaming like the voice of a Dalek, and yet confident. None of the syllables were given more emphasis than the others, and the Cybercontroller kept exactly the same tone with no variation whatsoever. "CLARA OSWALD." Clara stepped forwards again. This was going to be a long walk. "CLARA OSWALD."

"Yep," Clara said. "That's me." Another step. What do they want? She wondered. And why do they want me in particular?

"DOCTOR."

Clara blinked. That was new. Had they malfunctioned, incorporated her ruse so many years ago into their systems? Did they honestly believe that she was the Doctor?

"That's me!" Clara looked up at the ceiling. The voice had come from somewhere above them.

"HOW ARE YOU HERE?" The Cybercontroller asked.

"No." A man said, sliding a metal panel away and jumping down. For a brief second, air started to leave the ship, but he closed the hatch up immediately with a strange tool. "That is not the question."

Clara couldn't believe her eyes. His hair was grey, his face lined and old, his eyebrows bushy. Independently cross, he would say. The man wore a navy jacket, lined with red fabric, and in his hand was a tubular metal object with a blue light at the end—a sonic screwdriver, Clara remembered. She had read about it in notes. "Doctor?" Clara asked faintly.

"Clara?" He asked skeptically. "No, you're not Clara." He had a thick Scottish accent, and waved his hands around while he talked.

"Er, yes I am," Clara said.

"No," the Doctor said. "You're not. You don't…look like Clara. She has this thing with the eyes, they're too big. How do they even fit on her face? You don't have Clara's eyes. Very bad copy, if you ask me, which you didn't."

"WHAT IS YOUR INQUIRY?" The Cyberman asked.

"Oh, yes, the question," the Doctor said.

"I am Clara!" Clara protested, mostly, to avoid letting the Doctor see how surprised she was to see him. His hair was shorter than when they had parted ways for what Clara had thought was the final time, which meant that he still remembered her. This was just his inability to recognize anyone.

The Doctor squinted at her for a moment. "Clara?" He asked in disbelief. "I thought you had a thing."

"A thing?" She asked.

The Doctor waved his hands in the air. "A thing. With your boyfriend. That you don't say anything about. A date," he clarified.

Clara opened her mouth to tell him she had no clue what he was talking about, before thinking better of it. He didn't realize that she was in his future. He didn't realize that she hadn't seen him in six centuries. He didn't realize how hard it was for her to keep from hugging him. "Er, yes. Date. I was on a date with…" What was his name? She had been dating someone, she realized, but she couldn't remember his name. He hadn't liked the Doctor. "…with my boyfriend, when the Cybermen teleported me to this place. They were fighting some sort of war. I tried to call you, but I didn't have my phone."

"Yes," he said, seeming to know what he was talking about. "The Cyberiad Transportation Unit. Nasty."

"DOCTOR."

The Doctor turned to the Cybercontroller. "Mr. Glowy over here was sending out some very interesting Artron Energy readings."

"YOU ARE NOT AUTHORIZED."

"Forget about authorized," the Doctor said. "You're the one with Artron Energy readings off the charts!"

"YOU ARE NOT AUTHORIZED." There was the sound of thousands of metal plates clanking in unison as the Cybermen pointed their guns at the Doctor and Clara. Instinctively, Clara began to back away. The Doctor, meanwhile, began to point the sonic screwdriver at the large sliding door behind them, to no avail.

"Uhmmm," Clara said. "You have a plan, right? Please tell me you have a plan."

"No plan," the Doctor said. "I have a 'thing'. That's better than a plan."

Clara just shook her head. "What thing?"

"I have a question!" He shouted.

"INFORMATION REQUEST DENIED," the Cybercontroller announced. "HUMAN DESIGNATED CLARA OSWALD IS REQUIRED."

"Clara Oswald is required?" The Doctor said. "And why's that? What use is a normal, boring, human, when you've got a Time Lord?" He waved his sonic screwdriver in the air, hopefully planning some sort of escape.

"INFORMATION REQUEST DENIED," the Cyberman said. "THE DOCTOR IS NOT NECESSARY. HE WILL BE DELETED."

"No, no, no, no!" The Doctor said. "There will be no deleting. Clara, ask them why you're necessary."

"Er…they won't tell us," she reminded him. Clara didn't remember him being like this, barging in and forgetting incredibly obvious details. Nostalgia? She wondered.

"They might listen to you. You're required, apparently."

"Why am I necessary?" Clara asked loudly. Come on, Doctor. Surely you have a plan.

"CLARA OSWALD WILL BE THE VESSEL."

"The vessel for what?"

"THE CYBERIUM REQUIRES A VESSEL." The Cybercontroller stood up from its metal throne, eyes beginning to glow with unnatural blue light. It looked alive, and Cybermen were anything but that. Then, it held out its hand. From in between the joints leaked a silvery metal. It floated into the air, coalescing into a sparkling silver blob that pulsated with light.

"Right." Clara said. "That's the Cyberium?"

"CORRECT."

"…Why does it need me?" Clara asked.

"INFORMATION REQUEST DENIED."

Just then, at the worst possible moment, Clara heard a voice in her head. Me's voice, to be precise. Clara. Clara Oswald, are you there? Can you hear me?

What? Clara thought. How is Me in my head?

"Clara?" The Doctor asked, concerned. He grabbed her hand, waved the sonic screwdriver around, and smiled at the Cybercontroller. "Thank you for all the information," he said. The blue spheres around them began to spin, and then the two time travelers disappeared in a flash of light.

Everything was dark. Why was everything so dark? Clara hadn't died, had she? She was immortal, she couldn't die? So why was everything so dark? No! I've been converted into a Cyberman! There was a sharp, stabbing pain behind her eyes.

Clara. You can open your eyes, you know.

Oh, right, Clara thought, feeling silly.

I hacked your optic nerve; I should be able to see what you see now.

Clara looked around. She and the Doctor were in a small metal room, with a thin rectangle section of the wall slightly sticking out. Clara stood up, confused. "Where are we, and how did we get here?"

Good question, Me said.

How are you doing that? Clara thought.

You can't 'think' to me, in case you were wondering. You have to talk.

The Doctor, pointing his sonic screwdriver at the door, didn't look over at her. "I teleported us away. Unfortunately, I had to teleport us to the only short-ranged coordinates I knew weren't already occupied."

"How are you doing that?" Clara whispered.

"Are you talking to me?" The Doctor said without turning around. "Or are you talking on the phone to your boyfriend?"

"Er…I'm talking to myself," she lied. "Like, you know, 'oh, Clara, why do you keep getting yourself into trouble'?" She was still trying to wrap her mind around the fact that she was actually speaking with the Doctor. Clara had thought that she would never see him again—they were far too dangerous to stay together, nearly forming an entity that Gallifreyan legend would stand over the ruins of the planet. The Hybrid. Despite her fleeting memories, Clara remembered that well.

The nanobots that the TARDIS uses to translate, Me explained. I found the TARDIS. That's the good news.

"Bad news?" Clara asked, even more quietly. The Doctor didn't notice, this time.

Bad news is I can't get the TARDIS functioning without an influx of energy. Something drew it here.

"Can you get us out?" Clara asked the Doctor and Me.

The Doctor shook his head. "The lock's deadlock sealed."

"Everything's deadlocked sealed, for some reason," Clara said. "It's like the universe has a grudge against your sonic screwdriver."

"It doesn't." The Doctor seemed rather offended.

"I know," Clara said. "I was joking."

"Were you?"

"Yes. So, what do we do now?" Clara asked.

Hold on, Me told her. I think I can get into the networks from the TARDIS, if you give me a moment.

"That'll drain the charge," Clara whispered.

The TARDIS isn't going anywhere, Me reminded her. There's not much we'll be using the power for.

"Life support?"

"Life support," the Doctor said. "Clara, life support!"

"Oh. Erm, yes," Clara said, swinging her arms. "Life support. Is there enough air? If the door's deadlock sealed…" Of course, she didn't need to breathe, so it wouldn't affect her, but the Doctor's respiratory bypass system could last only so long.

"Wrong question," the Doctor said.

"Well, what's the right question then?"

"Where's the vents?"

Clara slowly began to smile. "Right, so where are the vents?" She looked around. "I can't see any."

"Neither can I! No. Yes. No. Shut up. Shut up, shut up."

"I'm not talking!" Clara protested.

"Shuttity up-up-up!" Clara opened and closed her mouth like a fish. "Listen," the Doctor whispered, putting a finger to his lips.

"I…can't hear anything," Clara said after a few moments had passed.

"Exactly." The Doctor looked around, examining the walls each in turn with his sonic screwdriver. "Metal, metal, metal, no readings." He touched the wall. "It feels like metal…but it isn't."

No readings?

"No readings?" Clara asked.

Clara, the readings are off the charts. Artron energy. This place is—

Me's voice stopped abruptly, and the Doctor grinned. "Wait, no—Artron energy. This is what I came here for. This isn't a prison cell, it's a Time Capsule!" His sonic screwdriver lit up as he scanned it over the wall. Then, the Doctor stuck his hand through the dull grey metal. Clara watched it disappear. "Come on!"

"Er, we know nothing about this except that it's a time capsule. Maybe we shouldn't—"

"No," the Doctor said.

"Well, what else do we know?" Clara asked. "Me?" She whispered. "Me, are you there?"

…energy…interfering…charge… Then Me was gone.

"Correction: we don't know that it's a Time Capsule," the Doctor said, and then stepped through the wall.

"Doctor!" Clara shouted. "Doctor! Doctor, are you alright?" She shook her head. Five minutes with him, and he's already doing his best to get himself killed. "Geronimo," Clara whispered, because the Doctor used to say that. Not in this body, but when he had been the other him, the other Doctor, before Trenzalore, before he regenerated.

Clara dived through the wall—

And hit solid metal. "Owwww," she moaned, standing back. At least she couldn't get bruises. Clara pressed her hands against the wall. It no longer wavered when she touched it. "Doctor!" She shouted. "Doctor! Doctor, are you there?" The Doctor didn't respond. Somehow, the Time Capsule had closed.