A/N: Yikes. Nothing can even be said about how late this one is. Er… at least it didn't take twelve years? ^^'

Thank you so much to everyone who commented in the interim – you guys are all wonderful! In specific, thank you to: GuesssWho, friendlyquark (No! No, not the kittens!), Person-without-a-FF.N-account (Thank you so much!), Linorea (I just hope I can get those updates posted a little faster in the future!), RiddleMeThis17 (Eee, thanks! ^^ It diverges from canon a few days after A Christmas Carol, though I actually started writing it before that. I am so slow.), versenaberrie (I think they've all noticed by now x3), saffarinda, somebodykillme, Solmea (Thanks for the PM as well!), GoodApollo, IsaGirl10, Guest (Thanks for both reviews! Alas, the Master's not feeling very huggy), Ithyl (Still planning to finish it eventually ^^), Beautifulspace, Dark Knight Warrior (I'm wondering how they'll manage that in the 50th, but he does always come back), guest, PlushChrome (Thanks for both reviews; I'm glad you came back to it! :3), MAH-BLACKBERREH (Thanks! ^^), Valiant rose (I'm not sure Rory would enjoy that much… o.o), kuhekabir, Lovely Rain Dancer (It certainly seems that way, doesn't it?), Dragoneisha (Poor Rory – he's so fun to torment though), Ginko-333, Lucillia, kyu000 (Thank you!) and Mango Supreme (Sorry for leaving it so long on a cliffhanger!).

Concealed in the hallway's shadows, the Doctor listened until he heard the soft creak of the TARDIS doors and the click of the latch. He poked his head around the corner, half-expecting to see Amy standing there with crossed arms and an obstinate air, but the console room stood empty no matter how far he craned his neck to look.

He turned back to the hall and sighed, rubbing his hand over his jaw with a wince. The usually bright roundels in the corridor cast only a filtered orange glow, muted with blue at the edges, and the platform glowed like a beacon in contrast, promising hours of repairs, innovations and everything else that wasn't dealing with the Master. His eyes lingered on it over his shoulder, but he drew in a deep breath and continued down the hexagonal corridor to the Master's room.

Without surprise he found the Master's door sealed shut. Though no sound came from within the room, the faint psychic rustlings at the edge of his mind revealed the Master's presence, and he leaned in close to the door. "What happened?" the Doctor asked, keeping his voice low, but there was no response other than the psychic sense retreating. He folded his arms and swayed side to side. "Something must have. Or at least I hope so, because otherwise we may have a very big problem."

"Another one? How many do you want?" came the retort, distorted through the metal door. "It's no matter of yours. Now run along and play with your pets – I'm sure there's some foodstuff you haven't desecrated yet."

"Listen to me; just for once, listen. Those memories, those shadows in your head, they're growing stronger, aren't they? And they're going to keep getting stronger, every day a little more, wearing you down until you've nothing left to fight them. But give me a few minutes to put some structure back and –"

"Right, I'll just open the doors and let you come waltzing on in; I don't think," the Master interrupted.

"You never do think. And in case it's escaped your notice, you only have one door now and it's this one right here," the Doctor said, rapping his knuckles against the bulkhead. "Which I certainly could open if I so chose. Ignore it all you want, but the longer we do nothing, the more likely that damage will become irreversible."

That was met with a snort, followed by the receding scuff of boots. "'We'?" the Master said, his voice briefly muffled. "It's nothing involving you, and I don't need your heroics. Much though I know you'd just love to charge in and save the day, I'm afraid your princess is in another castle."

"Could you at least attempt to not be -" the Doctor flailed his hand briefly "- to not be you for a moment and take this seriously?"

Inside the room, clothing dropped with a soft thud to the floor, shortly followed by a drawer being yanked open and its contents rummaged through. "Serious is boring, especially when you're involved. You get all doe-eyed and earnest and dribble sincerity on everything, and it's pathetic and embarrassing for all concerned. Now where the hell is that shirt…."

Ignoring the stream of muttered curses at the uncooperative chest of drawers, the Doctor scoffed and tucked his hands under his elbows again. "And what's hiding in a corner if not pathetic?" he mocked, but to no effect. He rocked back on his heels and continued with only partially feigned derision seeping into his voice. "Still, typical of you, keeping everyone at arm's length and attacking friend and foe alike. And why would you want my aid anyway? Much better to let yourself wither away - you wouldn't want to take the risk of someone actually getting close to you, now, would you? I suppose some people might call that cowardice, but me, I call it… no, never mind; I call it cowardice, too."

"Ouch! The sting! How ever will I bear the pain your words have wrought in my soul?" Another drawer was hauled out, banging against the limits of its tracks. "If you think that's going to affect me, you're worse at this game than I thought. What you call a coward, I call a man showing damn good sense, which certainly applies to keeping your sticky fingers out of my head. You'd leave nasty little do-goody fingerprints all over - it would take forever to clean. No maid service for minds, either. Maybe I should start one. Don't bother applying; you'd be terrible, and your legs would look ghastly in the uniform."

The Doctor pursed his lips and bumped the toe of his boot against the base of the door. He recognized that manic tone, swerving from one distracted thought to another in almost breathless fashion, and it never heralded anything good. The engine room grew more tempting by the minute. On the other hand, if the Master played himself out and became too exhausted to argue…

Settling back against the door frame, the Doctor straightened his bow tie and sniffed. "Curious how you're so worried about my intrusions but don't give a thought to everyone else's," he said. "You're an open book any passing stranger could leaf through at will or rewrite as he saw fit without you ever noticing the difference, but, oh, heaven forbid you allow me in, because I might meddle with something!"

The Master sniggered. "'Might'? Surely you mean 'would'. I've never known you once to pass up the opportunity of – hah!" His voice pitched up in triumph and he hauled something fabric out of the drawer, but the minor victory cut short as what sounded like half a hardware store cascaded to the floor of his room. Jangling and reverberating clangs mixed in a cacophony that gradually trailed off into tinkling pings, fading to the faint metallic rattle of small things rolling away for the corners, until at last silence fell. "...ah. You were saying?"

"What in the world have you got in there?"

"That's not what you were saying, Doctor; pay attention."

The Doctor's eyes narrowed and he tilted his head, easing over until his ear hovered next to the door. Hasty rattling and scrapings could be heard within, stray objects being rounded up and stashed away, but nothing to help him identify the exact nature of what had been dropped. "Yes, right," he said, straining his ears. "Well, as I was saying, then, it's not like you could keep anyone out, myself included."

"Don't forget with whom you're dealing, Doctor," the Master said with a sudden growl in his voice. "I don't need walls to launch an attack. If you push too far, someone will end up broken and it won't be me."

"Oh, talk, talk, snarl, snarl," the Doctor replied, flapping his hand in the air. "Heard it all before; let's have something new for a change. Even on a good day you're nowhere near strong enough to affect me psychically."

The Master chuckled slowly, the low deliberate laugh that never failed to send creeping shivers up the Doctor's spine. "Sorry, did I say you?"

A stab of fear pierced the Doctor's chest, and he snapped forward, coming to a quivering halt with the tip of his nose almost grazing the door. "You meant me," he said, his words echoing back at him as his breath condensed on the metal surface. "If you're wise, if you have a single molecule of sense left in that slurry you call a brain, you know that you meant me and no one else."

"Hah! Touched a nerve there, did I?" Steps crossed the room, coming to a halt just on the other side of the door. "You're so very predictable. Always the hero, self-sacrificing to a fault because you can't bear to see your little friends hurt. But they are anyway. And they forgive you and forgive you and say it's not your fault, and you let yourself believe it as they're destroyed in your name." He paused, blowing a whistling breath through his teeth. "How does it feel when you see the look in their eyes, that final second when they realise you're not going to save them? When you see the last shred of their soul evaporate into nothingness?"

"Stop it!"

"Would you like to see that in your precious Amy Pond's eyes? Her mind shattering, neuron by neuron, until she's nothing but an empty husk? A pretty one though, I grant you – I could have some fun with that before the end."

The Doctor heard another ping and distantly wondered if it was his own brain snapping. Engine room. Should have gone with the engine room. But enough was definitely enough. He drew in a long breath, waiting for his jaw to unclench enough to speak. "While we're on the subject," he finally said, very soft and cold, "at an estimate, how long do you think it would take someone with basic psychic abilities to turn you into their own personal sock puppet? Twenty seconds? Maybe less? There's nothing you could do to stop them and you know it; any cheap hypnotist could wave his hand and you'd do whatever he said, become his own trained monkey performing tricks for his amusement."

A surge of roiling anger rose from the Master, but the Doctor continued relentlessly, not caring that his voice was rising. "And this is just the beginning. It's going to get worse, much worse, until there's nothing left of you in your head. But when the memories take over you, when you can't even see or think or move because they'll be crushing your mind in a living hell every minute of your existence, at least you'll have the satisfaction of knowing you're in that state through your own stubbornness. It's already starting, isn't it? Even the Ponds have noticed it now. Not to worry; I'm sure they'll be very understanding and spare some pity for the pathetic wreck you'll become as your last vestiges of control slip away. You won't care though. You'll be a vegetable, a blank-eyed madman stuck in hell, alone, forever, and the best part, oh, the biggest joke of all, is that you just let it happen without doing a thing to stop it. Oh, how Rassilon would laugh."

Something crashed against the other side of the door with a shattering of glass, and the Doctor leapt aside and plastered himself against the wall, his hearts thundering. The pitiful clinks of brutalized glassware faded away, and he held his breath, waiting for the inevitable retaliation. The Master never had much of a span between 'deceptive calm' and 'murderous rage', and through the wall he could feel the other renegade's fury sizzling over the edge of his consciousness. Any second now…

The silence stretched on. After a moment, the Doctor frowned and slid cautiously around to the door again. Of all the things he might have expected, this was not among them. No rampage, no torrents of profanity, no threats of eternal suffering – it disturbed him, how still everything had gone. Even the faint background hum of the TARDIS seemed hushed. Finally the Master spoke, a vicious snarl that made the hairs prickle at the back of the Doctor's neck. "Burn in hell."

The grim finality to his voice brooked no further discussion. The Doctor banged the heel of his hand hard against the door, but he bit his tongue and forced himself to step away, coming to rest against a support on the far wall. He stretched his neck, gazing blankly into a yellow light overhead, and then shook his head, tight-lipped. "Right. Well, that's that," he said, his words clipped and sharp. "If you're so determined to refuse my aid, I'll wash my hands of the whole thing and you can find your own way out of this mess. But if it doesn't work, if you run out of time, don't expect to come crawling back to me. I want to help, I truly do, but I refuse to watch you destroy yourself again. Decide your course, and once your temper has settled enough to hold a civilized conversation you can tell me where to leave you."

He pushed away from the wall and stalked down the corridor. So much for that plan. He should have known talking to the Master would be as fruitless as ever. Cursed, stubborn, ill-tempered, idiotic -

"…Doctor?"

His steps faltered. It had been said softly, so low he had barely heard the word. Still, the suddenness of it with the hesitant rise at the end spoke volumes, and he was certain the Master hadn't meant to speak aloud. The Doctor paused and bowed his head, trying to will away the constriction in his chest. He should keep going – he knew that. The ultimatum had been cast and backing down now would only weaken his position. He had to stand firm, for both their sakes. And yet, for all the centuries that had passed, in that one word he could hear the child he had known, the little boy who'd once clung to him, terrified of being abandoned. Different name, different voice, but the fear behind it was the same as ever, both childish and ancient, painfully familiar.

Slowly he walked back to rest his hands against either side of the doorframe and sighed. "I'm here." The Master didn't reply, but the Doctor thought he heard the faintest of indrawn breaths break the fraught atmosphere. He bumped his forehead lightly against the coolness of the door, allowing his frustration to seep away until calmness settled around him. "I'll always be here. But you need to let me in. Being pigheaded does no good for anyone, least of all you."

"Who's pigheaded?" the Master grumbled. "You're the one who never lets it drop."

The tension in the Doctor's shoulders eased and he gave his bowtie another tug. The Master's voice was calmer now, despite the petulance, and the griping held more resignation than malice. It was probably too much to hope that he'd been swayed at all, but he did sound at least a little conciliatory. Not in words, perhaps, nor in tone, nor really in anything clearly perceptible, but there was definitely a faint sense of penitence.

"What if we made a deal?" the Doctor said, resting his shoulder in the doorframe and crossing his ankles. "You let me in long enough to get the basics done, and in return I give you what you want."

There was a pause, and the Doctor raised his eyebrows when he heard cautious steps near the door. "And what, pray tell, do I want?" the Master asked with an equal mix of suspicion and curiosity.

"More freedom to go where you please. If your mind is repaired, I needn't be so concerned about, oh, say you leaving the TARDIS on your own, or going to busier places you would enjoy. We can't do that now, not when you might come home with anyone in your head, but if you let me help you…" He left the sentence hanging and listened closely, stretching his psychic senses forward, and he could hear a faint rhythmic tapping against the wall as the other thought it over.

Finally he heard the Master shift next to the door, and he couldn't help but smile when he realized that the other Time Lord was unwittingly mirroring his own position against the frame. "I've got a better idea," the Master said, at which the Doctor gave an unsurprised shake of his head and muttered 'Oh, of course you do'. "All that would be is you letting me run the leash out a bit further. Not much interested in that, thanks. If you're going to have the audacity to offer me freedom, you'd better be willing to make good on that, and not with some trifle like unsupervised walkies. No, if you want me to cooperate with you, you're going to have to give me something of actual value. Take the isomorphic lock off the TARDIS controls; then we'll talk."

"And leave you with full access to the ship?" the Doctor said with indignation, straightening up. "I'm hardly going to give you complete free rein. I know you - give you an inch and you take a whole galaxy."

The Master shrugged, the fabric of his hoodie brushing against the wall, and strolled away from the door. "Then I guess that's it for the deal. Nice chatting with you; now go away so I can get some sleep."

A pronounced squeak of bedsprings followed, and the Doctor huffed. For a moment he'd thought he was on to something, but of course the peevish Time Lord would drive a hard bargain, even now. Contrary old idiot, he thought with a pout, crossing his arms again. If he was hanging from a cliff and I tried to pull him up, he'd demand payment for the privilege.

Still, no need to dismiss the idea out of hand, regardless of how unreasonable the Master might be. For a moment, the Doctor allowed himself to wonder what might result from giving the other man this victory. Utter chaos and devastation seemed a strong possibility. On the other hand… The Doctor tapped his chin lightly with his fingers. On the other hand, just how much use would unlocking the controls be to the Master?

The locks might have been necessary in the beginning, but lately the TARDIS herself had become a far greater theft deterrent than any lock. After all, it wasn't the isomorphic locks that sent lashes of electricity at the Master any time he wandered too close to the console, or that sealed the hallways when he tried to sneak into places he shouldn't. Without the locks… Nothing would actually change, the Doctor thought with a sly grin. Perhaps this was one carrot he could afford to sacrifice.

He cleared his throat and leant against the wall with his arms folded and one foot up, radiating casual coolness until he remembered the Master couldn't see him anyway. "What if I said yes?" he asked. "If I did promise to remove the isomorphic locks, what then?"

The room remained silent, and the Doctor started to worry that perhaps the Master had fallen asleep. However, after a long pause, the bed squeaked again as its occupant sat up. "What?" the Master said, and from his unguarded tone it seemed that this time he'd truly surprised the man.

"If you let me into your mind, exclusively for the purpose of setting up your mental defences, I give you my word I will remove the isomorphic lock," the Doctor said. "And after that, I won't push any more help on you unless you ask; you can do all the rest on your own - rebuilding your mental shields, blocking off the implanted memories, stopping the voices. Once you have a solid foundation to work from, it'll all be possible, and that's all I'm trying to give you, nothing more. Permit me that, and the locks will be gone."

"Go pull the other," the Master said. "You wouldn't let me touch those controls if the ship was on fire. Not that I haven't considered testing the theory." Despite the dismissive words, the Doctor heard the soft thud of boots crossing the floor, followed by a crunching of broken glass.

Once again the Doctor's hearts beat a wild samba against his ribs, but this time with eager excitement rather than fear. "I assure you, I am completely in earnest," he said. "So, deal?"

A few more seconds ticked past until the Master said, "All right, then. But you take the lock off first. To prove your intent."

"You already know my answer to that suggestion. I'm not trying to cheat you; I have every intention of keeping my word and you certainly won't get any better offer than this, but the locks stay on until you've filled your side of the bargain. If nothing else, it would be a fine mess if I removed them first and then someone used you to make off with the TARDIS. No, it's my way or nothing. What do you say?"

Moments dragged out as he waited for the answer. The Master was certainly taking his time, but the Doctor felt confident that even he couldn't refuse this particular bait. The offer might not have been entirely wise, but for now he pushed the doubts away and focused on the triumph of getting through to him at last.

In his distraction, it took a second to register in the Doctor's brain when the Master said, "No."

"What? But why not? You said yourself that -"

"I didn't expect you to actually go for it, idiot," the Master sighed. "I just thought it might shut you up for a bit."

"Right, fair enough," the Doctor said quickly, "but now that I have gone for it, why not accept? Really, you're the one who gets all the benefit here, so why keep resisting when it's so obviously in your favour?"

The Master settled heavily against the wall without responding. Judging by the faint tinkling sounds, he was poking around the shards of whichever mistreated object he'd smashed earlier. Probably a lamp. His room used to have a lamp.

The lack of any excuse in itself answered his question, and the Doctor's hearts sank as the brief hope flickered out again. "I can't do anything if you refuse to trust me," he said, closing his eyes with frustration and thumping his head against the door. "A few minutes of trust; that's all I need. You know that I would never hurt you."

The silence dragged out, and finally he heard the Master say quietly, "Yeah, I know that." Another pause, shorter this time, followed by a slight sigh. "And it doesn't make any difference. I can't; d'you understand that? I just can't."

The Doctor's shoulders sagged and he leaned against the door, sliding down to the floor and draping his arms across his knees. Well, there it was. If he'd accomplished nothing else for all his efforts, at least he'd gotten an honest answer out of the Master, though not one he'd hoped for. No matter how much time they had, he doubted it would be enough to erase a lifetime of mistrust, nor to mend the damage done by Rassilon. The ache in the Doctor's jaw gave testament to how strongly that particular trauma still affected the Master.

Still, there had been something there, if just for a moment, a tentative consideration rather than immediate flat denial, and a miniscule amount of progress was better than none. There would be better times to bring the issue up again, and the least he could do to reward that rare glimmer of candour was grant the man's wish to be left in peace.

"Okay," he said with a shallow nod. "Okay. We can find something else then, some other way. No matter what, I promise, I will not lose you to this."

The Master breathed a faint laugh and clicked his tongue. "I'm already lost," he said. "I was from the moment you fired that pistol and severed the Gate. The only question is which will go first: mind or body. And I'm afraid there isn't much time left for either."

A/N: And that's the end of this section, finally. I promise I'll try to do better with future updates. ^^'