Tag fic to episode 4x10 Midnight. This was an odd one to write because it's obvious from the episode that the Doctor was really quite unsettled by what happened on Midnight and I wanted to explore that... but it was hard to write him "weak" or being emotionally open and have him still feel in character. I hope I managed to strike the right balance.

All comments and feedback gratefully received.

Sometimes there is no darker place than our thoughts, the moonless midnight of the mind – Dean Koontz

It was perhaps a week or more after the events on Midnight that Donna realised something was really wrong. Perhaps even more than a week, it was hard to say for certain; it was kind of hard to keep track of time in the TARDIS, but they'd spent two days chasing (or, more accurately, being chased by) Luwathan Nightwalkers on Aidora and at least a day each in both 32nd Century Pnamixia and the Ancient Civilisation of Kloom (not to be confused with Clom, apparently) and when she came to stop and think about it and add up the time, it was surely at least seven days.

Seven days in which the Doctor didn't seem to have slept at all. Admittedly, he never seemed to need much sleep. She assumed he must have a bedroom somewhere in the TARDIS but she'd never seen him actually use it (and she could never seem to find it when she went exploring the vast interior, not that she was specifically looking for it or anything) and it was a common occurrence for her to find him wandering the corridors or fiddling around under the console or reading in the library room if ever she awoke at odd hours.

But she knew he needed some sleep. She knew cos she'd asked him once. He'd been his usual evasive self and just sidestepped the question with another vaguely rambling response, "Oh, less than you humans. Honestly, how can you spend so much time sleeping? Doesn't it get boring? Think of all the fun you're missing out on!" She assumed he must catch a nap from time to time while she was conked out for a healthy eight hours; she'd wake up and find him in the console room in a different suit – well, really, one of many extremely similar suits but with a different combination of shirt and t-shirt and tie – and, if possible, even more energised and enthusiastic than when she'd gone to bed. Honestly, sometimes just looking at him was enough to make her tired.

And really, that's what finally clued her in to the problem. That energy, that enthusiasm and vitality, was missing. It had faded slowly as the days passed and it was oddly like watching a wind-up toy slowly run down. The Doctor wasn't one for dwelling on things, in fact he'd made avoidance an art form, but he'd been truly shaken by his encounter on Midnight, arriving back at the leisure palace looking pale and lost, not speaking when she hugged him, just squeezing back almost fiercely, holding on to her for what felt like a very long time. In fact, he hadn't spoken for a while, not until she'd eventually untangled herself from him and got him seated at the table with a cup of hot tea in his hands. And their subsequent conversation had been oddly quiet; she'd honestly never seen him so distracted, so subdued.

But he'd shaken it off, or so she'd thought, once they'd gotten back in the TARDIS, throwing himself into piloting the ship with his usual cheerful energy. And if that cheerfulness had felt a little forced, then that was understandable. And if he wanted to forget for a while what had happened out amongst the diamonds then she couldn't really begrudge him that either. She knew from experience how good he was at not talking – well, actually, talking an awful lot really but somehow without ever actually saying anything – when the mood took him. So she'd let herself be carried along by his determined exuberance, just as she always was, and had let herself believe that he really was okay.

Except he wasn't okay. His exuberant energy, bordering on mania at times, had dwindled as the days passed and his rapid-fire speech had slowed and faltered, petering out into increasing periods of brooding silence. It was never a good thing when the Doctor was silent. She'd thought he was dwelling on things, the events of Midnight haunting him after all, despite his determined avoidance. She'd tried to lighten the mood, to snap him out of it… and when that hadn't worked she'd left him to his silence, thinking maybe he needed a little time to readjust.

And then he'd nearly crashed the TARDIS.

He'd been teaching her to fly the ship, bit by bit, and while she didn't remotely understand all the complicated functions and interactions that controlled their passage through the vortex, she knew at least the basics. Enough to notice when his usually sure touch fumbled and missed the lever he was reaching for. Before she'd finished drawing breath to warn him, he'd pressed the wrong button and the ship had lurched horribly, throwing them both to the floor with an awful, grinding, shrieking noise.

By the time she'd clawed herself vaguely upright, hanging onto the console for dear life as the TARDIS rocked and shuddered and groaned, he'd scrambled back to the controls and, in a flurry of switch-flipping, button–pressing and occasional hammer-bashing, managed to get the ship back under control, leaving the two of them abruptly gasping for breath, clinging to the console, as the room steadied back into normal flight.

He'd been wild-eyed, more than a little shaken, and deliberately avoiding her gaze.

"What the bloody hell was that?" she'd exploded, shaking from an adrenalin rush of mingled terror and relief.

He'd straightened slowly and, she'd realised later, unsteadily, his attempt at prevarication half-hearted as he offered her a weak grin. "Whoops. Umm. Minor technical issue. All fixed now." He'd kept his attention on the console, fiddling ineffectually with a few unimportant settings.

"Doctor," she'd had to consciously set side her anger and fear, make her voice deliberately calm because this was serious. "You hit the wrong switch. I saw you. You adjusted the vortex loop control instead of the helmic regulator." She'd shaken her head in disbelief. "I've never seen you make a mistake while flying the TARDIS."

He'd looked up then, reluctantly, and his gaze had been hollow and she'd realised, really realised, that something was wrong. He'd looked pale and drawn and tired and even as she'd watched he'd swayed a little, his grip tightening briefly on the console. And that's when she'd recognised his deterioration for what it was and tried to count back and think how many days it had been since…

"Doctor," she asked him gently, "when did you last get any sleep?"

"Oh, I don't need sleep," he flapped a hand dismissively, turning back to the console as he rambled, "Not like you humans – spend a quarter of your lives snoring, you lot do! D'you know I once nearly got eaten by a Yeti because the humans were all busy sleeping? Well, I say a Yeti… "

But she could tell his heart wasn't really in it and his words trailed to a halt as she interrupted firmly, "Doctor."

The smile he gave her was unsteady, his eyes too bright.

"I can't…" He sucked in a shaky breath and looked away, blinking.

She'd teased him once about being lost for words, finding it funny to see the usually verbose Doctor so off-balance. This was anything but funny. She waited, letting the silence hang between them.

He didn't look at her as he admitted, his voice low and raw, "I'm scared. I'm… scared to go to sleep."

He sounded incredulous, annoyed at himself. She reached out to take his hand and he didn't argue as she unwound his fingers from around a lever and tangled them with her own.

"C'mon," she told him.

Predictably, he resisted. "Donna…"

She turned and headed towards the TARDIS interior, ignoring his reluctance, pretending not to notice that he made no move to follow her until their joined hands pulled him forcibly after her. He muttered a complaint but made no attempt to free his hand from her grip. She remembered another time, a lifetime ago and galaxies away, when she'd grabbed his hand and dragged him along in her wake, nearly pulling him from his feet in her enthusiasm. And even longer ago, even before that, on the day that changed her life forever, she'd told him that he needed someone. Someone to stop him. She'd only seen half the truth then that she knew now; that sometimes he needed someone to save him… from himself.

He was still protesting as she pulled him out of the console room. "Donna, honestly. I'm alri…"

She didn't even bother turning round. "You're not alright," she interrupted bluntly, "not even the Time Lord version of alright." She'd drag him all the way to his bedroom if she had to – and wasn't that a thought she'd never envisioned having? Mind you, he was skinny enough that she could probably pick him up and carry him if it came to that. Not that it would. He was dead on his feet, stumbling after her meekly enough for all his protestations.

Right then. Bedroom. She stopped walking and looked around. She'd spent her first few days on the TARDIS getting continually lost before she realised that, bizarrely (though not really, if you stopped to think about the whole "bigger on the inside" thing), the internal layout was not always constant. Every now and then rooms seemed to randomly shift position while you weren't looking, corridors didn't lead where you remembered they did and you never quite knew for certain what you were going to find behind any given door. She'd soon learnt not to even try and understand how it worked and instead to rely on instinct; somehow it usually seemed that whatever room you needed (not necessarily wanted – at least as far as the TARDIS was concerned, the two were not always quite the same) would end up being nearby.

On a hunch, she opened the nearest door and found the Doctor's bedroom. She knew immediately that it was his if only by its sheer simplicity (well, that and the blue pin-striped suit jacket draped over a chair); the décor was simple and plain, the furniture minimal. This was a room where someone came to sleep, someone who didn't sleep much in the first place. The bed was neatly made and the room itself was, for the Doctor, surprisingly tidy. This obviously wasn't a place where the Doctor spent a lot of time; that was the console room. That was where he lived, where he seemed at home, dancing around the console, flipping switches and pulling levers, messing with the wiring. This room was simply where he came to rest when he needed to.

And right now, he needed to. She marched into the room, pulling him with her, and manoeuvred him around to stand by the bed.

"Sit," she ordered.

"Donna…"

"Sit, spaceman." She gave him a firm push to the chest and he wobbled off-balance and sat down abruptly on the bed, too surprised to resist.

"Donna…" He was still trying to argue though, a note of exasperation creeping into his voice.

"You, you muppet, are just about asleep on your feet," she informed him in no uncertain terms. "And Time Lord or not, if you don't get some sleep you're gonna make another daft mistake and get the both of us killed."

His expression of indignant stubbornness melted abruptly at that and he sagged, looking up at her with ill-concealed dismay. God, he was an idiot at times. She hadn't meant to be unkind but sometimes it took a few sharp home truths to get him to listen.

"And we can get into enough trouble on our own without adding dangerous driving into the mix," she added affectionately, unable to hold back a small smile.

"Hey, I'm not the one who tried to put a dent in the 1980s," he defended weakly. It was a half-hearted attempt but it was reassuring see him at least trying. She snorted indelicately in response and knelt down to unlace his sneakers, the action bringing an unexpected echo of maternal feeling, a too vivid memory of a motherhood that was never even real.

He jerked his foot out of reach, protesting, "I can take my own shoes off!" and the fragile bubble of memory burst and was gone.

"Fine," she agreed, a little snappishly, standing up. "C'mon then." She stood over him like a teacher with a rebellious pupil as he reluctantly crossed his ankle over his knee and worked the sneaker free, pulling it off without bothering to unlace it. It hit the floor with a dull thud, tossed carelessly into a corner, and was joined a moment later by its mate, leaving the Doctor sitting uncomfortably on the bed, barefoot in his suit, looking tense and unhappy.

"Take your jacket off," she decided.

He looked up at her with surprise and a little wariness and she rolled her eyes. "Don't worry, your virtue's safe with me!" she chided impatiently. "Just thinking it can't be that comfortable to sleep in. No ulterior motives, honest." She spread her empty hands pointedly.

He shrugged out of the jacket and let her take it from him; she chucked it on top of its blue twin on the chair.

He looked oddly young and vulnerable sitting on the bed in his just his shirt and trousers. He was pale and drawn and he looked exhausted but he was still tense, still reluctant. She pulled a chair over to the bedside and told him bluntly, "C'mon. Lie down."

"Donna," he was looking more uncomfortable by the minute. "I can't. I…"

"You're scared. I know." She sat down deliberately and looked him squarely in the eye. "Because of Midnight?"

He frowned, his expression turning pensive.

"Talk to me, Doctor," she pushed and he sighed, lifting his gaze to look past her, staring into nothing as he spoke.

"It took my voice," he said simply. "It… it got inside my head and it took my voice and I couldn't move. It was so… so cold and dark in my head and I tried to fight it but I couldn't break free and it used my voice to turn them all against me. All of them." He met her gaze earnestly. "I don't think I've ever felt so alone," he admitted quietly. "Or so helpless."

She grimaced at the thought of how close it had been; how close he'd come to dying out there in the diamonds and the deadly sun.

He scrubbed a hand over his face wearily. "I couldn't control it and I couldn't control them and… and stupid as it sounds," he admitted, "I'm afraid to go to sleep now. I'm afraid to let go of control, even for a second."

She nodded in understanding.

"You can't stay awake forever," she reminded him softly. "Sooner or later, you have to let go."

"I know." He nodded. "I know."

"C'mon," she encouraged. "Lie down."

He grimaced but this time he did as he was told, stretching his skinny length out on the bed, still holding himself stiffly, his hands clasped over his stomach. She reached over and pulled one hand free, taking it in her own hand and giving a quick squeeze. He looked over at her with hooded eyes in a solemn face and squeezed back. He was beginning to drift already, his body so starved of rest that his eyelids began to droop as soon as his head hit the pillow.

She stayed there, beside his bed, holding his hand as his eyes fluttered closed and his breathing began to even out… and she squeezed his hand reassuringly when, seconds later, he jerked back to awareness with a gasp, his eyes snapping open anxiously.

She gave him a rueful smile as he looked up at her and let out a shuddering breath.

"You can let go," she told him quietly. "I'll stay right here. You won't be alone."

He nodded but his body stayed tense and stiff.

"Talk to me," she demanded with a smile. "Let me hear that clever flipping voice of yours."

"Hah," he laughed shakily, a pale echo of his usual exuberance. But talk he did, slowly at first, telling her about the people on the bus, about the stories they had told of their lives and their families, about Driver Joe and Claude the engineer and a diamond landscape that no-one else had ever gazed upon before, sparkling in the sunlight. And as she let him talk he began to gradually relax, his eyes starting once again to drift closed, his words slowing and slurring.

She thought he'd fallen asleep when he squeezed her hand and drowsily murmured, "I was so scared, Donna. I was all alone… and I was so scared…"

"I know. But you're not alone now."

She held his hand as he slipped finally into sleep. And when he woke an hour later with a yell and a jerk she kept hold of his hand and she talked to him, letting the sound of her voice calm him as he gasped shakily, "It's gone. It's gone. It's gone." And she kept talking as he caught his breath and as he slipped irresistibly back into sleep.

And this time, he didn't dream.

Fin.