"the master unaging the doctor out of loneliness, sometime during the year that never was."
"Oh get up, you," the Master said, kicking at the straw-floored tent where the Doctor was sleeping. "Up, up, up! Uppity up up!" The Doctor tried to ignore the sharp kicks as they hit his ribs, legs, and arms. Slowly and carefully, he crawled out onto the cold floor of the Valiant. In the darkness of the unlit room, he could see the silhouette of the Master against the round porthole windows, glowing with stars. "Eaaasy does it," the Master said, taking the Doctor's arm and pulling him up hastily. Though his grip was firm, the Doctor couldn't help but note its gentleness.
"Look at you, though," the master winced. "A wrinkly old prune. You're repulsive. You're lucky I left the lights off, if I could properly see your face I'd probably vomit all over you. I was just about to tell you to have some self-respect and clean yourself up, gramps, and then I realized that this is all my fault. How funny is that?" Before the Doctor could open his mouth to reply, the Master pointed his laser screwdriver directly between his eyes. Suddenly, a flash of light; the Doctor could feel every cell of his body moving, dividing, merging. Blood pumping backwards, skin tautening against his bones. He fell to the floor, gasping for breath. He examined his hands. He ran his fingers through his hair to find it thick and brown once more. He was agile again, able, could run away. Could run at him. But the Master stood and watched, wry grin spread across his face. "Why are you doing this?" the Doctor asked. "What are you going to do to me?"
"I had a bad dream," said the Master, crouching down beside him. "You could even call it a nightmare. I dreamt that Gallifrey smoldered and blazed as Time Lords and Daleks alike screamed for mercy. Have you ever heard a Dalek scream for mercy? I suppose you have, seeing as it's all real for you. But oh, it was awful. Because they weren't screaming for me." His face was an inch from the Doctor's. "They were screaming for you."
"It was terrible," the Doctor almost whispered.
"But great. To have an entire planet at your mercy? I can't imagine anything more beautiful. You had every greater species in the universe in the palm of your hand! Do you know what I would have done for that sort of power?"
"I know. I know exactly what you would have done. I'm watching you do it as we speak. Japan, gone. Entire nations reduced to rubble. But you should know, despite everything you've done, everyone you've killed, I fo-"
The Master clamped his hand over the Doctor's mouth. "Oh no you don't. If this is how we have to talk, then so be it." He sat beside him, careful not to move his hand. "Alright. I talk, you listen, I let you say a word or two, and the hand goes back up. That's how it's going to work. Understood?" The Doctor nodded.
The Master stayed silent for a very long time, sitting back, holding the Doctor's mouth with one hand, keeping himself steady with the other. "I never thought you could do something like that. Not in – " he stifled a laugh, " – not in a trillion years. You, the one who always did the right thing. You hate guns. You hate seeing people suffer. How could you end the war, knowing full well that you'd be sending yourself into exile again, this time never to return? And how can you look me in the eye now, knowing that I would have done it in a heartbeat, that I would have enjoyed it, that I ran away?" His grip loosened. His hand was now merely hovering over the Doctor's lips, gently enough for him to speak.
"There was so much carnage. I knew it was the only way I could end their suffering, and I have to remind myself of that every day. You'll probably hate me for this, far more than you already do, but I think you ran because you still have some compassion left somewhere. You couldn't bear it, just like how I couldn't, but you had no means to end it." The Doctor turned to face him, and placed his hand over the other Time Lord's chest. "I haven't felt a binary heartbeat in so long. I thought I'd never feel it again."
The Master covered the Doctor's mouth again. "You were asking me out on a date, weren't you? Oh, that's not fair. I'm a married man."
The Doctor ripped the Master's hand off. "Right, about that. What were you thinking? Why, why would you do that to that poor girl? How did you even find her?"
"Oh, I was just buying some crisps at a convenience store, and she was there, picking up batteries. First pretty girl I laid eyes on. That's how companions work, right? Find pretty girls and take them places? Of course, you locked your TARDIS's coordinates, so I couldn't take her very far. But I learned from watching you, silly! I heard all about that little blonde chav you ran around with. And now that Martha Jones. You've only got eyes for pretty, convenient girls. And so do I."
"Don't you dare talk about Rose like that. I swear, I'll –"
"Uh-uh-uh!" The Master returned his hand to the Doctor's mouth, "no need to get so worked up over that silly little girlfriend of yours. Though I admit, I was quite impressed to hear about her looking directly into the Time Vortex. I heard she was saved by the power of love. How sweet."
The Doctor gasped and tore the Master's hand away again. "She's a million times the person you are. Don't you dare say another word about her."
"Where is she now, anyway?"
"Alternate universe."
"Of course. That must have absolutely broken your hearts. Don't you worry, I won't say another word about little Rose-y Wose-y. I'm only a little jealous. Just a tad."
The Doctor smiled. "Jealous? Come on. It was just you and me for hundreds of years. Do you remember the pranks we used to play at the Academy? I never thought we'd get away with any of them."
"Which is strange, because they were all yours. And who's the stuffy one now? When's the last time you've had any fun? Oh no, don't even tell me. I know it had to be the work of one of your darling companions. You're so hopeless."
The Doctor smiled. "Coming from a homicidal maniac, that is a truly damning assessment."
The Master moved his hand back. "Doctor, why do you have to stand in my way? Why can't you just let me have one little planet, filled with lesser beings? There's a place for you in my new world. Just say the word, and you can have your own throne. Right beside mine. Your own place in our new Gallifrey." He gently removed his hand.
"You know I can't do that, Master. And you know why."
"Well," the Master said, getting to his feet, "I know a lost cause when I see one. You could be so great, Doctor, if you'd only abandon these useless apes. But look, the morn, in russet mantle clad. I should get a move on, re-age you, start my day off right. Do you know just how invigorating it is to shoot Jack first thing in the morning? Start the day off with a bang, huh?" He smiled, wide and twisted.
"Master?"
"Yes?"
"Why don't you just kill me?"
The Master reached into his robe pocket and pulled out his laser screwdriver. "Then I'd be the only living Time Lord," he said, pointing it at the Doctor. "And I'm sure that would be awful lonely."