I was fascinated by the idea of the Tomorrow Windows - devices which could show the future of an individual. The Eighth Doctor and his companions encountered them in the novels. While I haven't read the novel myself, I have asked Marcus S Lazarus for help on this, and he provided it, so thank you for that, my friend. I've added a few different faces to Ncuti Gatwa and the ones on the run up to the official unveiling to the next Doctor. I felt there were dozens of possibilities for the Thirteenth Doctor's next life.

Enjoy.

Please let me know what you think.

x

Tomorrow Windows 13

By TimeTraveller-1900.

Everyone in the TARDIS yelped when the time machine accelerated through the Time Vortex, throwing them all to the ground; Yaz painfully tumbled across the room, and ended up close to one of the honeycomb-patterned walls, wincing before the Doctor was thrown across to where she was lying. The Doctor was lying on her back, her long coat askew while she lay on her back. Despite the pain, she was currently feeling from the acceleration, Yaz could not help but notice the smooth skin of the Doctor's legs…

Finally, the TARDIS crashed with a sound like a giant had uprooted a glass skyscraper and just dropped it again. Moaning in pain, the three time travellers slowly got to their feet. The Doctor flinched a bit as she rolled onto her side and looked around in confusion, and she gazed at Yaz.

"Yaz, are you okay?" The Doctor asked rolling around so she could get to her feet, and she got up groaning in pain before she held out her hand to Yaz.

Yaz took the Doctor's hand. "Ask me later," she replied as the Doctor helped her stand. "What the hell was that?"

The Doctor opened her mouth to give a clever lie, but she sighed, "I don't know."

And she really didn't. The Doctor had set the TARDIS to take them to somewhere fairly quiet following the crisis of the Flux and the immediate crisis of the Daleks, and the encounter with the Sea Devils and the pirates.

Yaz was looking around the console room. "Dan? Where's Dan? Dan, where are you?"

Dan groaned as he got to his feet, holding his head. He had been thrown out of Yaz's sight, which was why she hadn't been able to see him. "Over here, Sheffield. Nothing to worry about," he flinched at the pain he was in. "What happened? Why were we going so fast?"

"I'm not sure," the Doctor went slowly to the console and checked it over. Inwardly she found herself wishing her TARDIS console was more neatly laid out, like the one used by her first incarnation, or she had monitor screens on each panel so if something went wrong she could find out what was wrong quickly. "But we went over the Time limit.

"The Time limit?" Yaz asked, her tone hoping for answers as she and Dan slowly approached the console, but kept right out of the way of the Doctor as she worked.

"You can only travel a certain speed in the vortex, otherwise you run the risk of tearing a hole into the side," the Doctor walked around the console. She needed to know what that trip through the vortex was all about. For a moment she wondered if the TARDIS had been snagged by a piece of time travel technology and had been pulled along like a fish hooked by a line. It was possible; with the Time War long since over and Gallifrey now gone again because of the Master's discovery of the Timeless Child, time travel was more widely used in this new universe, and it was possible someone out there had found a way of snagging whatever was in the vortex and the TARDIS was just not able to fight it.

But she found no sign of anything like that. There was no sign of any energy field, no sign of a time corridor which had snagged on the TARDIS and pulled it along, no sign of a time scoop. For a horrible moment, the Doctor wondered if the Master had returned and he had decided to send the TARDIS somewhere where he could be waiting, with a trap in mind.

It was possible, she knew he had once forced the TARDIS off course in her sixth incarnation when she had been travelling with Peri.

The Doctor hoped not. She'd had more than enough of the Master to last a thousand lifetimes. She didn't want anything to do with him ever again. She had learnt her lesson; he was irredeemable and he was never going to be her old friend ever again.

And yet….

And yet she was reminded of the time in her tenth incarnation when the TARDIS took them to Messaline to be there for Jenny's 'birth' (she would not think about that time). It was certainly more plausible, as she checked the instruments, the more convinced she was something else had happened.

But despite what could have been the cause, the Doctor did know the TARDIS had landed. She activated the holographic scanner mounted on the console, but the systems were still shaken, so she powered up the wall scanner instead. The quality was poor, but she soon saw the TARDIS had landed in what looked like a strange garden with dozens of scattered ornaments.

Tearing her eyes away from the scanner screen, the Doctor checked the environment outside. It was a breathable atmosphere, she noted; no viruses, no sign of anything lethal like Chen-7, or anything lethal like that. And the gravity was fairly average. But what she didn't like the look of was the yearometer reading, there wasn't one, so she didn't know what year it was outside. But the Doctor was curious about why the TARDIS had arrived there.

"Doctor, where are we?" Yaz asked.

"I don't know. I don't know what period of time we're in, or if we are on a planet, a star, or a ship. I just can't tell. But there's a breathable climate out there. We were brought here for a reason and I want to know what it is," the Doctor marched towards the doors, and a moment later she heard her companions follow her to the doors.

X

The air was fairly cool and moist as they stepped out of the TARDIS, and as she looked around the garden, the Doctor could see beautifully crafted and carved animals - at least she assumed they were animals - dotted in between the plants. As Dan and Yaz stepped out of the TARDIS, she shone her torch over the police box shell of her ship. The outer shell was a bit battered, probably as it experienced temporal friction within the vortex, but the police box shell was perfectly fine and the light on the top was still intact.

Yaz was peering into the darkness beyond the lights which were dotted about the garden "What is this place?"

"I don't know," the Doctor said, looking upwards and she saw the sky. It showed the blackness of space, but she didn't recognise the neighbourhood of stars and planets. But she was aware they were moving. Were they on a rogue planet, a world which had been torn or simply left its orbit and was wandering the stars? It was possible for that to happen in any world.

Dan looked into the darkness. Cupping his hands to his mouth, he yelled, "HELLO?"

"Dan, don't," the Doctor hissed.

"I was only calling-," Dan tried to say.

"We don't know what's out there, Dan. We arrived here for a reason, and we have to find it. Come on, and don't wander off either of you," the Doctor said, but in spite of her words, she grabbed their hands and pulled them forwards.

X

The garden was quite large and as they walked along the paving slabs, the three time travellers were becoming more mystified by what they were seeing.

Dan looked up. "That's space," he pointed out, "Are we moving through space?"

"Yeah, we are, planets move as they orbit the sun," Yaz grinned teasingly at Dan. "Didn't you ever study the planets?"

"Of course I did, and I know planets move!" Dan retorted defensively.

Suddenly the Doctor stopped ahead of them and the two humans nearly ploughed right into her.

"Doctor?" Yaz asked. "What's wrong?"

"Look at that!" Dan hissed as he looked over the Doctor's shoulders. Yaz followed his gaze. It was a mirror, but as she looked closely at the mirror she realised it was a very unusual one. It was both ornate and yet it gave Yaz and the others the feeling that it had once been a massive crystal which had been hewn, cut and smoothed into a mirror. It towered over the three time travellers effortlessly.

The Doctor blinked as she studied the mirror. It was there and yet there was something odd about it according to her time-sensitive senses. Slowly, the Doctor stepped closer, and the others followed behind her. As Yaz got closer to the mirror, her reflection on the roughly hewn surface became clearer and more defined.

But then something happened to it.

The reflection of Yaz changed from the woman she was now, showing her in a full police uniform.

"Hey, wow!" Yaz whispered in awe as she noted that everything in the uniform that hinted she was a probationary officer was gone. She could see the sergeant stripes on her shoulder epaulettes, and as she looked at her reflection she saw that the her in the mirror was a few years older and she looked happy but there was something about the eyes that made the reflection Yaz look solemn.

"What is it? How is it doing that?" Yaz asked.

The Doctor groaned. "I think it's a form of Tomorrow Window."

"What's a Tomorrow Window?" Dan asked.

"It's a piece of time technology. I encountered one a few regenerations back. It was invented to show people their future and was known to be extremely accurate," the Doctor hesitated. "I was several possible future versions of myself in the same instant before it settled on my next true incarnation." Suddenly the Doctor had a good idea why the TARDIS had brought her here. The TARDIS knew she had begun to feel the impending shadow of her next incarnation and she wanted to reassure her.

The Doctor didn't want to see her next regeneration. No way.

Meanwhile, Yaz was looking at her potential futures. Yaz and her friends watched as Sergeant Yaz Khan became a plainclothes police officer, and it looked like the years of investigating crime had taken its toll on Yaz. They saw moments where Yaz's boyfriends and girlfriends just left her, leaving her alone. Yaz was chilled by the sight and realised that nothing had happened between herself and the Doctor.

Yaz shook her head. She had longed to have a normal life, with a good steady career, and a family. Suddenly the image changed, showing Yaz as a more carefree nurse. She smiled when she saw small children who looked like they had inherited her features running around.

Dan himself saw he and Diane were dating before they separated, leaving him alone. The years passed and the future Dan clearly had nothing, and he eventually died alone despite being loved for being a nice guy. Reflexively he denied the future, and he looked deeper and closer, and the Tomorrow Window obliged by showing him an image of himself happily marrying Diane, and they both worked at the museum together, laughing and wowing the crowds while he did extra work, and they both made donations and worked in a soup kitchen to help starving, homeless people.

He had always liked helping others, so seeing this was a joy despite the earlier depressing image.

"Hold on, why is showing us different futures?"

"The future is always in motion besides important moments."

"Yeah, but-."

"Dan, I've seen the end of the universe. I was there when Earth was destroyed and when the sun expanded. At that point, I didn't know anything about the whole mess with the Flux. I never knew we'd shunted the whole thing into a different timeline and the potential for the universe to be destroyed happened," the Doctor said, gazing at the Window.

The Doctor was feeling her resolution crumble and she realised she could not just run from this, no matter how tempting it was for her. The Doctor stepped forwards, gently moving into view of the Tomorrow Window, remembering her encounter with the technology in her eighth incarnation.

As before, she saw flashes of images; the TARDIS console, Yaz's smiling face, and some kind of train as it moved through an energy conduit which made her wonder if it was a hyperspace tunnel or a wormhole network. Her hearts nearly stopped in horror when she saw a flash of Cybermen, their armoured silver bodies glinting menacingly while their emotionless, mask-like faces.

Yaz saw them as well. "Cybermen?!" She yelped. "They're in the future?"

"They are always in the future, Yaz," the Doctor replied, already accepting the fact Cybermen were coming.

"What's a Cyberman?" Dan asked confused.

"A robot-," Yaz began.

"Cybermen are cyborgs, part machine, part organic. They were once people struggling to survive, so they decided to hack away at their bodies, replacing organs and limbs with machines and prosthetic limbs and covering them with armour before they erased their emotions because what they were doing made them scream," the Doctor interrupted, her voice dark and bleak. Old. Remembering the different histories of the Cybermen; remembering Mondas, Telos, Pete's World, the Mondasian ship in that black hole's inexorable grip…

The next image was something that horrified the three of them.

Daleks.

Hundreds of them.

But the image that horrified the Doctor and Yaz the most was the flash showing the face of a man with dark skin and black hair.

"The Master," Yaz whispered. "He's going to come back!"

"He always does, Yaz," the Doctor sighed, realising that, like her fourth, seventh, tenth and twelfth lives, she was going to lose another incarnation because of the Master's plans.

"The Master? Who's he, then?" Dan asked, knowing already this was not going to be good.

"The Master is a Time Lord like me, Dan. We were friends a long time ago. But things became strained and eventually, we became enemies. The last time I met him, he admitted he had destroyed Gallifrey, the homeworld of the Time Lords," the Doctor replied.

"What? He'd kill his own people? Why?" It was beyond Dan's comprehension.

The Doctor didn't really want to get into a discussion about the Timeless Child and what it had done to the Master's mind to hear it, especially after the other Time Lord had dedicated his lives to proving himself as the Doctor's superior, only to discover the Doctor was the one to help create Time Lord society. How could he beat that?

Fortunately, the flash of images (she was sure she saw images of Kate, Tegan and Ace; what were they doing there?) disappeared and the Doctor saw an image of herself reflected back. For a moment nothing happened and then the reflection of the Doctor began to glow with golden red energy before she transformed into a woman, perhaps a couple of decades younger physically, with long brunette hair.

"Whoa, what was that?" Dan asked.

"A potential future me. Regeneration. It does that every time I regenerate, my whole body changes," the Doctor explained briefly as she took in the potential future Doctor's face before the reflection of her current self came back, and then the glow of regeneration reappeared.

The potential Doctor was another woman, this time with an oval face.

And then the reflection of her current self returned again, before changing with the glow of regeneration. The Doctor smiled and perked up when she saw the long red hair of the physically slightly older woman with the expression of a grin always on the horizon, but there was a quirk in the eyes the Doctor was unsure of….

And then the reflection of her current self returned again. The glow of regeneration happened, and a young Asian girl appeared with glossy black hair. She was on the small side with delicate features. The Doctor scrunched up her face in annoyance. Another small incarnation?

But her reflection appeared again. When the glow of regeneration energy died down, she was surprised when she saw a tall man who looked like her tenth incarnation. Unbidden she remembered the Curator who looked like her fourth, saying that in the years to come, she would choose old faces to revisit but only the favourites.

But before the Doctor could properly process what this meant in the long term, the reflection of herself reappeared and she changed yet again. This time the Doctor in the mirror was a tall black man with close-cropped hair.

"Whoa," the Doctor whispered, looking at the reflection of the man in the mirror. She had never been black before (the Ruth her didn't count, really since she didn't remember that life), so she looked at her potential future self with interest. She had been interested in some of them, and the prospect of regenerating back into a form like her tenth was interesting to her.

But whether or not this was her future or not, the Doctor could not say.

A blonde-haired young woman appeared with a bright, somewhat crazy smile made herself known after the glow of regeneration, and after her was a tall black woman with long hair in a ponytail with a determined look on her smiling face. The next potential Doctor that emerged out of the glow of regeneration shown by the Tomorrow Window was a large black man with a grizzled-looking appearance.

She knew she would become one of these people soon enough, and she knew any of these faces could appear at any point when the Master, the Daleks, the Cybermen, Kate, and that train appeared. This was why you should never know your own future, you never knew what you were going to get.

And then the reflection changed back to her current self before the glow of regeneration revealed a tall brunette woman wearing a bright smile. This future Doctor disappeared, reverting back to the Doctor currently in charge. But it wasn't to last.

After the glow of regeneration faded, the new Doctor was revealed as a woman with dark, strawberry-blonde hair with a quirky smile on her face.

The Doctor sighed. This was the problem with regenerating, you never quite knew what was going to come out of the change. But with the Tomorrow Windows, the possibilities offered only served to make things harder and more difficult to process until they actually happened.

Author's Note - The Doctor's I envisioned were Hayley Atwell - a favourite - and Lily Collins, and Ruth Wilson (let's face it, her lethal quirkiness in Luther made her perfect as a psycho). The last one was Ncuti Gatwa. I also added Daisy Ridley, Sasha Alexander from Rizzoli and Isles for her quirky demeanour, Idris Elba, and Margot Robbie.