A/N - Just to make things clear, this story contains the Master as played by John Simm, and O/the Master as played by Sacha Dhawan.

PLEASE HEED THE TW! This takes place in Nazi Germany, and I'm sure I don't have to explicitly mention how messed up their language/thinking was. Sacha Dhawan is of Indian descent - but the Nazis weren't a particularly discriminatory bunch of people and so wouldn't have looked past 'non-white'. I love Sacha, he's a great actor, so there is absolutely no disrespect intended towards him.

20th March, 1944

Today, Herr Lavell and I decided to combine our classes by visiting the High Fens and climbing to the top of the Signal de Botrange. That, of course, was their physical activity for the day, and once they were at the top, then I gave them their Worldview lesson. I think it gets the point across much easier when they can see the lands that I'm talking about.

Of course, young Herr Einschell continuously jabbered on about my being 'Mister Master'. I don't know why on earth he was accepted into this school; he is rather irredeemably stupid, but his father is one of the most important members of the Nazi Party in the area, and goodness knows Einschell certainly looks the part. He is also rather freakishly strong, which I suppose was the deciding factor.

Still, that strength of his didn't help him when he somehow lost his footing on the way back down. Not too seriously injured, they said once they'd gotten him to the nearest infirmary – alas – but enough that he didn't return with us to Aachen. I don't think his squad will miss him too much.

A knock on the door caused the man writing in his journal to pause. "Kommen sie," he called, laying his pen down on a spare bit of paper. The nib was terrible, and was liable to leak ink everywhere if left horizontal for too long.

"I beg your pardon, Herr Master." One of the kitchen girls pushed his door open and dipped into a quick curtsy. "There's a visitor for you. He's waiting on the patio outside. He, er…" The girl chewed on her lip for a moment. "He requests that you bring your fob watch out with you."

Herr Master frowned at her. "My what?" he demanded. "Who is this man?"

The girl paled and ducked her head. "Please, sir," she squeaked. "He just said to tell you to bring the fob watch with you."

Scowling even harder, Herr Master shot a quick glance at where the old tarnished watch was lying on a shelf. It was so old that he had no idea where it had first come from, and it didn't even work – he had no idea why he hadn't gotten around to throwing it out as scrap metal yet – but its location could almost be called pride of place, if one didn't know any better.

"Tell the gentleman I'll be out in a moment," he instructed the girl, and waited until she'd shut the door behind her before getting to his feet. Crossing the room, he stood in front of the shelf, considering the fob watch. For an old, rusty relic, it held a strange fascination for him. He could end up spending countless hours staring at it, lost in who knew what thoughts, if he wasn't careful.

A noise from outside caused him to startle, and he realised he was on the verge of getting lost again. Shaking his head to clear it, Herr Master scooped the watch from the shelf and shoved it into his trouser pocket. As he left his room, it vaguely occurred to him to wonder how his visitor even knew he had it.

The man waiting for him was a Negro.

Herr Master stopped in his tracks when he spotted the man, leaning casually against the wall of the school. His hands were in his trouser pockets, propping his long overcoat open and showing off the Wehrmacht uniform he was wearing. "Did you bring it?" the man asked, an excited grin spreading across his face as soon as he saw Herr Master. His gaze was intense as he stared at Herr Master, fixated on the other man's face. "Did you bring the watch?"

"I—" Herr Master had been about to deny it, about to demand to know who this person was and why they thought they could order him about, but instead abruptly found himself holding out the fob watch.

"Open it," the Negro hissed. Then, "No! Ooh, I know! We should do it together!" And before Herr Master could do more than blink once in surprise, he was standing in front of Herr Master, hands wrapped firmly around the one holding the watch, and pressing.

The fob watch clicked open.

Immediately, a cloud of golden sparkles rose up and went poof in Herr Master's face.

He blinked, coughed

…and froze.

Oh…

Images, sensations, voices all poured into his mind in a torrential flood that was at once both alarming and unnervingly familiar. Oh my god, I can't believe I did it again! a thought complained.

"What did you do?" demanded Herr Master . . . no, the Master, as the whirlwind stopped and everything settled back into place. He gazed down at his hands, as the other man in front of him clamped his hands over his mouth and let out a delighted giggle. "What did you do?!" he demanded again, reaching out to grasp hold of the man's overcoat and shake him.

"I thought it was about time we had some fun," the man said, his voice still pleased, as though the threatened violence meant nothing to him. He grinned at the Master.

The Master let go of him with a snort of disgust. He couldn't believe he'd disguised himself as a human again. After the last time had gone so wrong – no-one had mentioned the watch to him, drawn it to his attention, he could only half-see it as his mind danced around the perception filter, and so he'd been left powerless for so long and grown old and useless and decrepit – he'd sworn that he wouldn't do that again. And yet, here he was. Shedding the human disguise of Herr Master – ha! – like a snake shedding a troublesome skin.

But not by his design.

"Who are you?" the Master asked the other man, still grinning inanely at him. Oh, wait a minute… He recognised that brand of insanity. He'd had that brand of insanity until just recently – or centuries in the future, whichever way you wanted to look at it. "Oh, you're me," the Master realised. He took half a step back and gave the other version of himself another look over. Hmm, a future version? Or a previous one that I don't remember because he won't remember? Mixing and merging timelines was always so tricky…

"Yes, I'm you," the other Master agreed. "Or maybe you're me. Who knows? But you can call me . . . O."

"O?" The Master frowned again. What kind of a name was that?

"Oh, yes," said O. A little giggle escaped him. "Or oh, dear. Ooh, or oh, god!"

The Master rolled his eyes. A previous incarnation, then. One that hadn't had that annoying drumbeat removed by the Gallifreyan High Council. "What do you want?" he asked. "Why remove my disguise?"

O bit his lip in what was apparently supposed to be a provocative way, ducking his head but flicking little glances up at the Master through his eyelashes. "I told you," he replied, "I thought it was time we had some fun. I'm waiting for the Doctor to catch up to me, so I might as well do something to pass the time."

"You're wearing a Wehrmacht uniform," the Master pointed out. "Isn't that 'doing something'?"

"Well, yes," said O, glancing down at himself as though he'd forgotten he was wearing the thing. "But that's part of the plan; it's not for fun."

The Master sighed and rolled his eyes again. "And what, exactly, do you consider 'fun'?" he asked.

"Thought you'd never ask," said O, gleefully. "This!" And he lunged at the Master.

The Master let out a grunt of pain as his head smacked against the wall, and then a further noise of surprise that was muffled by O's mouth enthusiastically pressing against his own. O's hands had gripped his lapels to push him back, but now they uncurled and slid up and over his shoulders, O's thumbs edging up to brush against the Master's neck.

"Oh, yes," O breathed, pulling back just enough to speak. "I was a fool to deny us this before."

The Master didn't even get a chance to do more than draw a breath – What? Deny us? What before? – before O's mouth was back on his, nipping and teasing. The Master found himself kissing back, his hands on O's hips to steady them both. They would find themselves in a spot of bother if anyone came out of the school and saw them now – even if interracial relationships were still allowed in this time and place, barely, homosexuality was even more illegal than normal under the Fuhrer's rule – but the Master found he didn't really care. It wasn't like they could put him to death, or imprison him, after all. He was a Time Lord.

"You're thinking too hard," O murmured, nipping his way along the Master's jaw. "Can't have that, now, can we?" He abruptly sank his teeth into the Master's throat, at the same time pressing his body hard against the Master's. And he was hard, too. The Master could feel him, hot and heavy against his stomach, even through several layers of cloth.

"I never knew I liked it so rough," the Master panted, his hands tightening on O. He slid a foot sideways, angling his leg between both of O's, and abruptly shifted, spinning them so that O landed against the wall with a thump, breathless and laughing.

O's hands moved, slid upwards to cup the Master's face as he pulled him back into a heated kiss, licking and nipping at the Master's mouth as though he were eating an ice cream cone. He did a strange little shimmying movement, and the Master had to tear his mouth away from O's, gasping for breath as the movement caused a delicious friction in all the right places. O lifted a leg and curled it around the Master's hip, somehow managing to pull him in even tighter against O's body.

"Come on, come on," he hissed.

The Master tilted his head down and scowled at the other, obviously more impatient, version of himself. "This would be a lot easier," he said, pointedly, "if I could use a hand…"

"Where's your sense of competition?" gasped O, grinding himself downwards against the Master. "I'm nearly there, and you need to touch me to get me off?" He suddenly gave a breathless giggle. "Of course, I'm already using me to get myself off. Talk about self-love!"

"Ugh." The Master rolled his eyes in exasperation. A lot of the looks he'd gotten once he'd allowed his Harold Saxon guise to slip suddenly made a lot more sense if this was what his insanity looked like from the outside. Damn the High President for doing this to me!

O interrupted his thoughts by grinding down against him again, just as the Master thrust upwards. "Oh, yes!" O gasped, clutching harder at his shoulders.

"I thought that was supposed to be my line," the Master muttered, and did it again. Whether or not O was actually 'nearly there', the Master himself certainly was. In fact, if O kept squirming like that…

He barely managed to get a hand over O's mouth, as O stiffened and then tried to throw his head back in a yell as he came. The Master himself leant in and bit sharply into O's shoulder as the sensations overwhelmed him, and he came too.

"There now, wasn't that fun?" O asked, giggling to himself yet again. His leg slid to the ground, allowing the Master to take a small step back. The Master grimaced. Getting back up to his room was not going to be pleasant. "Of course…" O tapped a finger against his lips. "You have been visible to anyone who may have been watching from Gallifrey…"

The Master paused. O had a point. He'd hidden himself away here after leaving Gallifrey so as to avoid the High Council's notice. He was fairly certain that Rassilon, at least, would have been very interested in where he went after the High President kicked him off the planet. But he hadn't been here for very long before O had arrived and torn his disguise away. To any Time Lord watching, it would have been the blink of an eye.

And the Doctor did so love to interfere in his little pet race's history. O had said he was waiting for the Doctor to arrive here. He couldn't take the chance that the version of the Doctor that arrived would correspond with his version now.

"Yes, it's probably time I was going," he said, finally. He took another step back and grimaced again. "Once I change," he added, and headed for the doorway he'd exited the school from earlier.

"Yes, time you were going," O chortled to himself. He grinned, and pressed his hands against his mouth to stop the excited noises that wanted to escape. "Time for the next part of our journey," he added in a muffled whisper, and then reached into a pocket of his overcoat, pulling out a small silver object. "Just had to make a… tiny adjustment!"

O couldn't hold in the glee anymore. He leant back against the wall, tipped his head to the sky, and laughed, and laughed, and laughed.