Clara rested her head on the cool metal wall. If she could cry, she would, but working tear ducts didn't come with being extracted from one's time stream. Looking back through the window, Clara could see the Doctor lying on the ground. His chest wasn't rising or falling; his time had run out.

No. This is not happening. I am going to fix this, that's what I'm going to do. I'm immortal. I can't even get hurt…well, physically injured. It still hurts. But I'm sure not existing will be a lot worse.

Getting up, Clara backed away from the door until she had gone as far as she could go. Then, she ran at the door, bracing herself for impact as she rammed the glass and—

Clara fell back against the floor, her head spinning and her side aching as if she had just run into a brick wall. Thankfully, the pain dissipated after a moment because there was no physical damage to cause it. And there it was, a tiny little crack in the door. Razor-thin, but there, undeniably there. Carefully, she picked herself up and backed away, running at the door yet again. Twice more, Clara rammed the glass entrance.

On the fifth time, Clara burst through the glass as it shattered around her. She closed her eyes, keeping the tiny shards of glass out, but they pierced all over her. Clara hit the ground, screaming as she felt the glass dig into her skin. It's not real, Clara reminded herself, crawling towards the Doctor. There were no splinters in her; they had been sucked into the time vortex. Clara couldn't change, couldn't age or die or bleed. She wasn't of this world, and now it was paying off.

Gradually, Clara picked herself up, moving over to the Doctor. She felt his pulse—buh buh buh bum, buh buh buh bum, buh buh buh bum. The double heartbeat of a Time Lord's binary vascular system. It was weak, though. She had to get him out of here, and fast. Clara tried to pick him up, but found that he was much too heavy.

Something was leaking out of his nose, his mouth, his eyes—a silvery grey fluid that rose up in the air, floating. The Cyberium, Clara thought, in awe. It settled down on her skin, but didn't enter her. "Have to send it back," she muttered. "How do I do that? Doctor, how do I do that?" But the Doctor was unconscious, unable to help her, and even if he was awake, he thought she was some sort of imposter. And maybe I am. "Is that what I am?" Clara asked. "Nobody? Just…just me?"

"No," said a muffled voice that made Clara look up. "I'm afraid that name's already taken." Standing on the slivers of glass was Me. And behind her was the TARDIS, still stuck in the form of a rock. She was wearing an oxygen mask, since there was none left in the air, but Clara could see her smile behind it. Me walked over, kneeling by the sphere. "I've had eternity to learn how to do this," she said, sticking her hand into the mess of wires that were spilling out from it. Clara began to drag the Doctor's unconscious body towards her TARDIS, wincing as she pulled him over the glass shards on the floor. Me rolled her eyes, and closed up the sphere, holding her hand out in the air.

Clara stepped over to it, trying to push the Cyberium out into the time machine. "Come on," she said. "Go. Go on." It floated up from her hand, leaving a tingling feeling behind, and into the metal sphere. Then, Me pressed a few buttons on the bottom of the machine. It began to spin rapidly, causing Me to back away.

"Should be good," Me said, wiping her hands on her dark shirt. "And now for the cleanup."

"Five minutes." Clara stood halfway inside of the Doctor's TARDIS. It had developed that Me had lost contact due to the high level of Artron Energy in the ship, and had come back to check that Clara was alright. After taking the remaining rebels home, she had come back and materialized her TARDIS as close to the center of the readings as she could. "I'm sorry," Me said genuinely, "but any longer and the timestreams will start to break down. You're not meant to meet him again."

"I understand," Clara said, closing the door behind her. No, I don't, Clara thought. I could tell him the truth. I could travel with him and we'd find a way to make sure time doesn't break down! I know we could. What's one more impossible story? Don't I deserve a happy ending?

No, she reminded herself. We nearly tore the universe apart. One of us had to forget—we can't travel with each other, or else we'll become the Hybrid. Five minutes. Five minutes to say goodbye. Properly, this time. Even if he doesn't know it. The Doctor lay propped up against the stairs to the second level. It wasn't ideal, but at least he was conscious. Well, here it goes.

"Clara?" The Doctor asked.

"It's me," she said, kneeling down next to him.

"You're not…no, you are. Your smile is right." He continued to lay against the steps, still recovering from lack of oxygen. "Do your eyes always look like that?" The Doctor asked. "All wide and deep and sad." They were silent for a few moments, staring at each other as the TARDIS hummed away in the background. "Why are you sad, Clara? You're Clara, I don't know why I ever thought any different. But why are you sad? You should be happy! You're about to go on a date with your boyfriend when I bring you back to Earth, you shouldn't be all mopey."

"Back on Earth," Clara said quietly, "there is a girl named Clara Oswald, and she is having a great time. After this, you go pick her up, and you go take her somewhere wonderful. Because I may be a good liar, but I wasn't lying when I said I was from your future."

"That's impossible…you travelled through time and space on the TARDIS, our time lines can't cross out of order, or reality would be torn into pieces."

"Yes," Clara said. "Doctor…" What do I say? Clara wondered. What do I tell him? What should be the last words I ever say to the Doctor ever again? But she didn't know. There wasn't anything she could say, wasn't anything that fit, that felt right. She looked out the window and saw Me holding up a single finger. One minute.

Clara leaned in to hug him, pressing her chin against his shoulder. "Are you still travelling with me?" The Doctor asked, drawing back.

"You know I can't tell you that," Clara said. She stood up. "Never stop running, never stop saving people. And never stop believing in impossible heroes, because I'm looking at one right now." She smiled, because suddenly she knew the exact right words to say. In millions of different times, Clara had said the same words to him. Sometimes he heard them. Most of the time he didn't. Because Clara Oswald had a message that she always had to tell the Doctor. Clara walked towards the TARDIS doors. "Run, you clever boy," she said, turning around to meet him in the eye. The corners of her mouth twitched into a smile. "And remember me."

Slowly, Clara lifted the cover of the diary. The last time she had written it was over half a century ago, and she had forgotten where she had placed the only record of her past life. After meeting the Doctor, Clara had searched all over the TARDIS until it took pity on her and lit up a trail to the room where she had hidden it. The first, crinkled page was stained like parchment paper. On it, in Clara's neat handwriting, was:

The Memories of Clara Oswald

The Impossible Girl

Cautiously, as if afraid she might tear the page to shreds with one false move, Clara turned to the beginning of the diary. There was a picture, there, a picture of a man with a stubbly beard and short hair, dark skin and a smile with brilliant white teeth. It was taped to the book, and somehow it stayed stuck to the page. The colors had faded, over the years, and some of it was worn away. Clara had used to touch it, holding her memories of this man close, but she had worn away some of the paper over the centuries.

Blinking, Clara began to read the first page of the diary:

My name is Clara Oswald, and I am the Impossible Girl. I was born to Ellie and Dave Oswald, and my mother's maiden name was Ravenwood. Fitting, I suppose.

I blew into this world on a leaf, and I will blow out of this world on the wings of a raven. Clara, when you're reading this, you may have forgotten everything but you and Ashildr (or Me, if you've finally started calling her that) in the TARDIS. So, just like how Ashildr kept a diary of her present so that her future could remember, I will do the same.

We travelled the world with a man called the Doctor. Even as I am writing this, memory of him fades in and out. First, he was young, with dark hair and a bowtie that he was obsessed with. Then he regenerated and became was a Scotsman, with grey hair and lines in his face. When people met the Doctor, they were scared of his appearance, but deep down, he was a wonderful person. Even if he liked to hide it. He doesn't remember us; he had to forget because if we stayed together, we would become the Hybrid. He agonized over whether he was a good man or not, in his early days in his new face. We weren't sure. But eventually, he decided he wasn't—he was an idiot with a box.

And what a wonderful box it was. The Doctor's TARDIS was stuck as a police public call box, although I don't think we'll forget that anytime soon. He would leave the breaks on because he loved the sound. We met the Doctor because Missy gave his number to us in a computer repair shop, and he was absolutely mystified when we called him.

We fractured ourself through the Doctor's timeline to save him, sacrificing ourself in the process. Of course, he saved us. That's what the Doctor does. He saves people. Then, he wonders why we believe in impossible heroes.

And yet the Doctor was not the best person we have ever met. He was amazing, but there are things that we could never say to him. There was someone we were willing to betray him for. I don't remember quite what we did, but we betrayed him once, for another wonderful person. There was fire and lava and so much smoke. We had to try so hard to keep from coughing, because then he wouldn't believe we were serious.

This man is Danny Pink, and we loved him, and he died. He was run over by a car and we literally went to hell and back to save him. Before he died, we were apologizing to him. We were apologizing over the phone, and he wasn't paying attention to the road he was walking on. It was our fault, though he'd never say that. When we were talking to him, we told him that we loved him. That "I love you" were our words to him and we would never say them to anyone else ever again.

He had a chance to cross back over, after everything was done, but he gave it up to save a child he had accidentally killed in battle. The Doctor was our idiot with a box, but Danny Pink was a good man. So, Clara-in-the-Future, you must never forget him.

Clara couldn't cry—she was frozen in time, and her heart couldn't beat and she didn't even need to breathe. Her tear ducts wouldn't let her. But she wanted to. Oh, god, she wanted to cry so much. Instead, all the pain stayed bottled up inside her, and Clara turned the page, unable to bear it.

…and I remember our adventure now, the one with the flat creatures, from a 2D world. We met that boy—do you remember that boy? He was a graffiti artist, he's the one who called us and told us that he had a tattoo counting down. Rigsby. That was the one. The TARDIS was all tiny, and had to go into siege mode. We tricked the 2D creatures into feeding it external dimensions by creating a graffiti drawing of a door handle they had made 2D. And we got to be the Doctor for a day. He was upset, of course, that we turned out to be such an excellent Doctor. That's what lead to our death, after all; like Icarus, we flew too close to the sun…

Clara let out an anguished cry, flipping more pages. They ripped and teared, some falling out of the book entirely, a flurry of pages and paper. White paper butterflies with torn wings, the memories they held flying away, forever lost as they fell from her past.

…Me nearly met herself, today—we had to do everything to keep the timelines from crossing…

…was an evil group of robots who wanted to destroy time itself; we took care of them with a…

…and the skeletons sitting in the water—they were Cybermen all along, I remember…

Forcing herself to calm down, Clara began to carefully flip through the diary, anxious to lose any more of her precious memory.

…and she had the most amazing laugh. My gran would tell me stories when our mother was out. They were the same ones, over and over again, but we loved listening to them. We would memorize the words and she would leave gaps for us to fill them in. What was her name? Did it start with an A? A B? It could be Calliope or Ursula, for all I know. Her name, her name, what was her name? Oh, God, I can't remember her name!...

…why can't I remember?...

…he was dressed as a monk, I think. He never told me why. There was a girl, from a book, but I don't know what she was doing there…

Clara tore through the book, mesmerized by the neat black handwriting and the forgotten words. She was distantly aware of the door sliding open, of Me entering the room, but she ignored it in favor of her memories.

…and I was so upset with those children. What were their names again? I was their nanny for years, but I can't remember their names!...

…I think there was another me, there, but she was evil. And sort of not evil. There were Zygons, but I don't know what they were doing, or how it ended!...

…and it was Trap Street, but I don't remember why we called it that. Me will remember where it is, she wrote it down in her diary, so I can still go back there to face the raven…

…this place. It was a century ago, I think, or maybe more. But I try to remember and my brain swims with all the information. It's too much, and I feel as if I'm drowning in a sea of half-forgotten memories…

…what's the point in all of this? I've lived far longer than I'm supposed to, and I'm forgetting everything now…

…my mother's hair. Was it brown, like mine? I don't know, and I don't dare cross my own timeline to check. I just want to remember her hair…

…and sometimes I can't help but wonder what the Doctor's eyes were like. Were we in love with him, once? I don't know, and I don't suppose I ever will…

"Clara," Me said. "Clara, what are you doing?"

"Reading," Clara said quietly. "No, I'm remembering." She looked down at the book.

…and I thought, "I knew a girl named Courtney once." I can't seem to remember what she was like, though. I think she was nice. Sweet. But I can't remember…

…I was reading through my notebook, and in the beginning, it says that we blew into the world on a leaf. How? What leaf? Was it green? Orange? Red? I had a leaf, once, and I gave it up, I think. It must not have been important to me…

…and I know that we can't keep running forever, but that's still a very long time…

"You're really thinking about doing it."

"Going back?" Clara said. "Just go away. Please."

"Clara, you've lived what, six hundred years? There's trillions more to live."

"I used to be so terrified of dying," Clara said, her voice far-off. "I'm not now. Funny how once you die, you're not scared of it anymore. I've faced my fears. And now it's time to face the raven."

"Are you sure?" Me asked.

"No," Clara said loudly. "I'm not. Please, just leave me alone for a little bit." Me slipped out silently, closing the door behind her and leaving Clara alone in the room.

…and we truly thought that the Doctor was going to leave us there for the rest of our life. There was that lizard-woman, and her wife. I can't remember their names or what they looked like. But he came back…

…I remembered something! The place where we worked, it was called Coal Hill School…

…Me ripped out a page of her diary at some point, and she has always regretted it. What did she want to forget so much? There are so many missing pages in our diary, and we don't remember ripping them out. What was so horrible that we believed it worth forgetting?...

…I wish I could draw, maybe that would help me remember what people looked like…

…I saw a memorial for myself, when we accidentally ended up on Earth again. Clara Oswald. There were lots of flowers. I forgot how pretty Earth flowers were…

…there was this strange creature, and I think he was a general of something. Oh, I was so scared. That's all I can remember: the fear and the darkness…

…I'm Souffle Girl for some reason and I can't remember why…

…and we met this boy, Yaron. He was bright and excited, and he had nothing left of his home. I almost offered to let him travel with us, as that alien had asked me. I don't remember what he was called, and lack the energy to look it up. But just before we beat back the Daleks, he fell, and I found his body broken on the ground. How easy it is for these human bodies to break…

…art lessons from Da Vinci; there was this strange man there who kept talking to Da Vinci like an old friend. All curls and these giant eyes that popped out of his face. He had this giant scarf, too. Terrible dress sense…

…how did I celebrate my birthday when I was a kid? It seems so pointless, now. It's just another day, when you've lived for five hundred years…

Clara stepped into the TARDIS console room. She wore a blue sweater, the same blue sweater that she had worn on the day of her death. "I'm ready," she said.

"No," Me insisted. "You can't just go…it's been so little time."

Clara smiled sadly. "It's been six hundred years, Me."

"And now you're going to go too. Another immortal who wasn't trying to kill me, and she decides to go to her death," Me said forcefully.

"It's my choice," Clara said. "And I'm ready. I saw the Doctor, Me, I saw the Doctor and he smiled and looked into my eyes. I don't want to forget that. I don't want to lose my diary and forget everything about who I am. Maybe I already have. But I don't want to die as someone else, someone who's not me. For the first time in so very long I've remembered who I am. My name is Clara Oswald, and I have loved and I have lost and I have lived. I had a story, and it was bloody good. And now it's time for it to end."

Me looked over at her, into her eyes, and saw her resolve. It's time to face the raven, Clara thought silently. "Fine," Me said. She pulled a lever, set in a few coordinates, and the TARDIS began to teleport itself away. Then it phased in, the brakes still on. Vrwoorp, vrwoorp, vrwoorp. It was the most wonderful sound in the world. "I can't go with you," she said, smiling slightly. "The Time Lords aren't exactly friendly with me. They don't like immortals."

"That's fine," Clara said, walking to the door. "Goodbye. Just…"

"What?" Me asked.

"You're not alone, Me. The Doctor has lived for such a long, long time, and he's never alone."

"So?" She asked. "You're leaving. Then it'll be just Me again. Travelling in the TARDIS. Me, myself, and I."

"You don't have to be," Clara said. "You don't have to be Me. It's not just you, there's other people in the world."

"They all leave in the end," Me said.

"Yep," Clara told her. "But if you run hard enough, you can get in a good life. And that's the beauty of time travel. It's another chance."

"Maybe," she replied, devoid of hope.

"Ashildr," Clara said, "you have a wonderful name. Use it. Please."

"Ashildr," Me said, her voice suddenly light. "Was that my name?"

"Yes."

"It was so long ago," Me said wistfully. "I was so young back then." She considered it. "Ashildr. I like that name."

"Bye," Clara said, opening the TARDIS door. It was so simple, far too simple for the final parting of two very good friends. She pulled Ashildr into a hug, wrapping her hands around the shoulders of her fellow immortal. But even immortals have to die, when their time comes. Everyone must face the raven in the end.

"Goodbye, Clara Oswald," Ashildr said. Clara slipped out of the console room, onto the dusty red surface of Gallifrey.

It was a long walk to the Citadel, but Clara went towards the shining city, step by step. When she reached the gates, her shoes were streaked with the rust-colored sand. A group of Time Lords waited for her there, just as she had expected.

"You should not have come here, Miss Oswald," a bald, dark-skinned woman told her. "You know what we have to do."

Clara smiled. "I'm ready," she said. "Bring be back."

Clara stepped out of the clean white room, back onto the cobblestone of Trap Street. The darkness of the evening was lit by the light that escaped through the cracks in the shutters of the houses. Everyone had fled from this alleyway, for death by Quantum Shade was a terrifying thing to witness.

A step forward, and then another. The raven hovered in midair, frozen in time and ready to enter her. Clara hadn't breathed in a long, long time. What was the point, when she didn't need it? But now, she did. It was the only thing keeping her brave, the only thing that allowed her to walk towards her death for the third time. In, out. It was such a strange feeling, both exhilarating and frightening at once.

"Let me be brave," Clara whispered. She could see the Doctor watching from the shadows. Clara had told him not to—knowing that he was there would make it even harder for her. But she hadn't expected him to listen. Clara sighed. He hadn't listened to her either, when he told her to stop, that he couldn't save her, that her time had run out. And because of that, he forgot her. Because he refused to just let her die.

Here I am, Clara thought. Dying. She breathed again, enjoying the feeling of air passing through her lungs, as she turned around to see the Extraction Chamber behind her. She nodded to the General, who nodded back respectfully, and then turned back around to face the raven.

Well, she thought, if Danny can do it, so can I. She'd said the same thing, centuries ago (minutes ago), when she'd learnt that there was nothing Ashildr could do to save her.

"Let me be brave," she whispered again, as the Extraction Chamber glowed white and began to close its portal. Clara had seconds to live. "Let me be brave."

And then it happened, as time began again. Years, Clara had lived without it, and now, it was the strangest sound in the universe.

Bah-Bum. A heartbeat. A final heartbeat.

Then the raven entered her, her arms held out to her sides, her face upturned to face the sky.

A little girl giggled as her mother pushed her on the swings.

A ten-year-old read aloud a passage of a book in class, her voice clear and confident.

A dark-haired girl peered over her mother's shoulder, reading the souffle recipe in the cookbook.

A young woman stood by her mother's grave, wiping the tears from her eyes.

A twenty-four-year-old watched two children playing, wishing that she had gone travelling instead of agreeing to watch a family friend's kids.

A dark-haired woman stared in shock as a little girl's head rotated around to reveal nothing but clear glass, shaped like a spoon.

A lost young woman stared out at nothingness, calling desperately that she didn't know where she was.

A brave girl who wanted to be a hero was falling through reality, splintering herself through the Doctor's timestream.

An uncertain Clara held out her hand, knowing that if this strange new man really was the Doctor, he would come back for her.

A twenty-eight-year-old stood in front of the Doctor, throwing the TARDIS keys into lava one by one.

A dark-haired woman faced the raven on Trap Street, and whispered "let me be brave".

A young woman in a waitress's outfit listened to the beautiful melody that came from the Doctor's guitar, and suggested that some memories become songs.

An impossible girl laughed with Ashildr as they learned to pilot the TARDIS.

An immortal woman picked up a young child and carried him out of the fire.

A weary Clara tried to remember her mother's name.

A woman so much older than she seemed watched a Dalek ship explode.

A deep-eyed time-traveler watched as Cybermen destroyed a world.

A dark-haired immortal looked into the Doctor's eyes.

Souffle girl smiled.

And Clara screamed.