Set during "The Day of the Doctor," so familiarity with that episode is recommended. However, the first part replicates the important part to set the scene, so you should be able to understand what's going on without having seen the episode, I think.

Hunched forward, the Eleventh Doctor regarded his two selves, the Tenth Doctor and the War Doctor, out of the corner of his eye. He had an idea, a wonderful, terrible idea.

The Tenth Doctor stared in disbelief, with a slight tinge of horror. "You're not actually suggesting that we change our own personal history?"

"We change history all the time. I'm suggesting far worse," he said, his voice quiet. His eyes unfocused as he thought about it further.

"What, exactly?" Glad at the chance to postpone the action he didn't want to take, the War Doctor was very willing to listen to any idea, no matter how preposterous.

"Gentlemen, I have had four hundred years to think about this." He made up his mind and straightened up. There was hope and determination in his voice. "I've changed my mind." Pulling out his sonic screwdriver and twirling it in his hand, he pointed it at the trigger of the Moment and activated it. The trigger retreated back into the weapon's casing. A dawning realization appeared on the Tenth Doctor's face, and he rubbed his hand over his mouth and jaw as he turned away to think.

"There's still a billion billion Daleks up there, attacking." The War Doctor eyed the Eleventh Doctor as he put his screwdriver away.

The Eleventh Doctor nodded, wagging a finger at him. "Yeah, there is. There is." Clara smiled at him. It was changing. It was all changing. She wasn't sure how, but there it was.

"But... there's something those billion billion Daleks don't know." The Tenth Doctor's face now also shone with hope.

"Because if they did, they'd probably send for reinforcements," the Eleventh Doctor quipped.

Clara still wasn't sure. "What? What don't they know?"

"This time, there's three of us." His eyes glimmered with impish glee.

The War Doctor froze. His jaw dropped, as the Eleventh Doctor's plan formed in his mind. He slapped his forehead with both hands. "Oh! Oh, yes, that is good. That is brilliant!" The Eleventh Doctor danced around the shack.

The Tenth Doctor's eyes widened as the plan also appeared in his mind. "Oh, oh, oh, I'm getting that, too! That is brilliant!" Turning around, he ran to his TARDIS and leapt, slapping high up the door jamb.

"Ha, ha, ha! I've been thinking about it for centuries!" The Eleventh Doctor spun and struck a triumphant pose.

The War Doctor continued celebrating, gesturing wildly like his final successor. "She didn't just show me any old future. She showed me exactly the future I needed to see."

Sitting on a haystack and unseen by the others, the Moment smiled. "Now you're getting it."

The Eleventh Doctor frowned. "Eh? Who did?"

The War Doctor ignored him. He blew the Moment a kiss with both hands. "Oh, Bad Wolf girl, I could kiss you."

"Yeah, that's going to happen." The Moment smirked and vanished.

The Tenth Doctor's face fell. He stared at the War Doctor, his brow furrowed. "Sorry, did you just say 'Bad Wolf?'"

Not privy to the Doctors' telepathy, Clara was still lost. "So what are we doing? What's the plan?"

The War Doctor and the Eleventh Doctor gathered around her. "The Dalek fleets are surrounding Gallifrey, firing on it constantly."

Recovering from his shock, the Tenth Doctor joined them. "The Sky Trench is holding, but what if the whole planet just disappeared?"

That wasn't enough to clear it up for Clara, and if anything, was rather confusing. "Tiny bit of an ask."

"The Daleks would be firing on each other. They'd destroy themselves in their own crossfire." The Tenth Doctor's hands mimed the firing of laser cannons at each other.

"Gallifrey would be gone, the Daleks would be destroyed, and it would look to the rest of the universe as if they'd annihilated each other." The War Doctor's face beamed.

"But where would Gallifrey be?" asked Clara.

"Frozen. Frozen in an instant of time, safe and hidden away." The Tenth Doctor's eyes were brilliant, and his hand puffed open, like a cloud of steam disappearing into the spring air.

The Eleventh Doctor smiled. "Exactly."

"Like a painting," whispered the War Doctor.

Clara smiled.

"Now," the Eleventh Doctor popped up and started pacing, "we have to get the calculations going. It's going to take the TARDIS hundreds of years to do it, and the more of them we can get, the more likely this will work. How do we get the word back to me, the first me?" The Eleventh Doctor hunched over and thought, tapping his temples with the fingers of both hands.

"Back to Totter's Lane, I'd say," the War Doctor suggested. "I was there for several months, so we're bound to hit that time frame easily. Any other time would be rather hit or miss."

The Tenth Doctor shook his head. "No, we need to get me started as early as possible. Every moment I can give to the calculations, the more likely we'll succeed."

The Eleventh Doctor straightened up. "Then we start at the beginning. By using a little trick I learned..."

The Tenth and War Doctors looked at him, confused, then they smiled simultaneously as the telepathic plan hit them. "Brilliant!" exclaimed the Tenth Doctor. "Where'd you learn that?"

"Spoilers!" The Eleventh Doctor grinned, though his eyes were sad.

The Tenth Doctor didn't notice. He turned and jogged into his TARDIS.

"I've a hike back to my TARDIS. Be there soon." The War Doctor bundled the Moment back into his sack and headed out of the door, his step light.

"What is it, Doctor? What are you doing?" asked Clara.

"I'll tell you on the way."

. _ . _ . _ . _ .

Escorted by four berobed Time Lords, the boy tried his best to look stately and serious while having to skip a bit to keep up with the tall adults. All his short life, he had been training for this moment, but he was terrified. He was terrified that he would make a fool of himself. Terrified that the Time Lords would tell him that he wasn't good enough and wouldn't even let him take part in the ceremony. Terrified that he'd forget what to do. Terrified of his classmates' mockery. He wasn't terrified of the ceremony itself. Later on, his older self would reflect that he had had no real concept of what was about to happen, and thus had no idea that it was the one thing he should be terrified of.

The walk to the site had been long, or at least long enough that his terror had built to a fever pitch. When they finally stopped, within twenty feet of round metal frame, about five feet in diameter, built on the top of the hill, he breathed deeply, trying to calm himself. And again. And again. Then he clenched his fists and swallowed, trying to prevent himself from hyperventilating.

The Time Lord that had led the procession stood in front of him. "You will now close your eyes. I will lead you to the Untempered Schism. When I tell you to, you will open your eyes and gaze into the Schism. You will continue to look into it until I tell you to stop. Do you understand?"

The boy nodded and closed his eyes. He could feel his hearts pounding hard, almost painful in his chest. A large hand closed around his shoulder and pushed him gently. He stumbled his way slowly as the hand guided him, until its reverse pressure indicated that he should stop.

"Are you prepared?"

He wasn't, but he nodded his agreement anyway.

"Open your eyes."

His vision was filled with the unbridled power of the time vortex, churning and writhing. There was nothing else: he was no longer standing on ground, or breathing, or feeling his hearts pound. He didn't have a physical body. He was enveloped in - no, he was the time vortex. He could see all of time - past, present, future - with all of its infinite possibilities. He could feel his mind rebelling, telling him to close his eyes and run away. And it was yearning to learn more, to explore time and the universe. And it was collapsing, under the weight of the incredible wonder before him. One moment, he couldn't bear it, and the next he wanted it to never stop.

What was out there for him? He willed himself to push out into the vortex, to search for all of the possible futures and see himself in them. There were planets and galaxies and nebulae, civilizations and faces of people of all species, all speeding by him too quickly to remember, and all suffused with the deepest, most comforting blue. And then he saw Gallifrey. His home, and yet not his home. But this time, it was burning, from a war bigger than he could imagine. And in this war, amid the fires and the ruined buildings and the piled corpses, stood a man, his hands, dripping in blood, poised over the trigger of a terrible weapon. He saw only his back but he knew who he was: someone he didn't want to become. Tears stung his cheeks - he suddenly remembered that he really was just flesh and blood - and he wanted to run away, never to see this man again.

At that moment, the man turned and looked at him. In his eyes, the boy saw hope. The man spoke three words, in a slow, raspy voice. "Make the promise."

"Stop."

A hood dropped over the boy's face and his connection to the Untempered Schism was broken. The hand turned him around, then removed the hood.

"Are you all right?"

Sobbing, the boy wiped the tears from his eyes and nodded.

. _ . _ . _ . _ .

"Oh, Grandfather, this is the most beautiful ship!" Susan ran around the console, gazing at the controls and smiling happily.

"That it is, Susan. Now, let us get going, shall we?" The old man began flipping switches and turning knobs. The time rotor started to pump, making a groaning, whining noise as it worked. "There. We have left Gallifrey now."

"This is so exciting! We're going to see the universe! But first, we should look through the rooms here. I should dearly love to have my own bedroom."

"So you shall, Susan. But you go on ahead. I have something I must do right away."

Susan stopped, concerned. "What is it, Grandfather?"

He paused before answering. "I made a promise, a long time ago, and I am keeping it now. Go on. It doesn't concern you."

Susan leaned over to kiss her grandfather, then ran off into the TARDIS interior.

The man punched buttons on the console, entering the data, coordinates, and times he saw a long time ago, in the eyes of a man he would run from all his life. As he did so, he whispered to himself, "Never cruel or cowardly. Never give up. Never give in."

Finishing the entry, the Doctor nodded. "The calculations have begun."