The occupant of the upstairs flat couldn't have been further from Craig's mind as he moved about the kitchen, teapot in one hand, spoon in the other. Behind him, a woman raised her head – something had caught her eye and she stopped, placing the keys in her hand down on the kitchen table.

"Craig, what's that on the ceiling?" she asked.

"What's what on the ceiling?" Craig replied without turning.

"That." The woman pointed, and Craig glanced up to see what appeared to be a patch of black smudges spread about one corner of the ceiling and creeping about a foot down the wall. "It's coming from upstairs. Who lives up there again?"

"Just some bloke," Craig shrugged, returning his attention to the tea and spooning sugar into the mugs.

"Hm." The woman pursed her lips thoughtfully at the dark patch, but turned away to settle herself on the squashy leather sofa of the living room that opened onto the kitchen. Unseen by either occupant of the room, the smudges began to darken, the edge of the patch crawling outwards and downwards across the white paint, spreading until it had almost doubled in size.

"So what's the plan tonight?" The tea finished, Craig headed over to the sofa with two mugs, handing one to the woman who smiled. "Pizza-booze-telly?"

"Yeah, pizza-booze-telly," she agreed. A resounding crash startled her from her tea and she raised her eyes to the ceiling with a frown.

"What is he doing up there?" she wondered. From the landing came the sound of fizzing as the lightbulb glowed brightly and then died again, and Craig eyed the ceiling, puzzled. "You put the advert up yet?" the woman added.

"Yeah – did it today," Craig answered, dismissing the bizarre sounds as he placed his mug on the coffee table beside the woman. "Paper shop window. One, furniture available immediately, shared kitchen, bathroom, with 27-year-old male, non-smoker, £400 PCM – per calendar month – suit a young professional," he recited.

"Mm, sounds ideal," the woman approved. A trilling of a cellphone came from behind them and she stood to answer it. "That's your mission in life, Craig – find me a man."

"Yeah," Craig laughed, not quite meeting her eyes. "Otherwise you'll have to settle for me."

"You'll have to settle for me first." A smile crossed Craig's face and he fidgeted, averting his head towards the bookshelf while the woman retrieved her cellphone from a jacket pocket. "Oh – Melina again. What?" she demanded of the caller, probably more harshly than she had intended. "Right…" As she breathed an exasperated sigh, Craig found his attention once more wandering to the patch encroaching on the clean white paint of his ceiling – like mould, it looked, or maybe dry rot… Curious, he stepped up onto a footstool for a closer look. "Yeah, but I've kind of got plans," the woman was saying. He reached one arm up to brush at the patch, but at her next words, he drew back and turned, indignant. "No, it's nothing important – it's just Craig."

"Oh, thanks Soph!"

"Sorry – you know what I mean," the woman, Sophie, apologized in a whisper, covering the mouthpiece of the phone. "O.K., I'll talk…uh…I'll talk to Craig. O.K." Crestfallen, Craig stepped down from the footstool and did his best to swallow his disappointment at the all-too-familiar apologetic look on Sophie's face. "Ugh – now she's having a Dylan crisis on top of the Claire crisis. It could be another all-nighter. I'm sorry but I really should…go…do you mind if I…?"

"No, not at all," Craig answered quickly, with what he hoped was a casual enough air to mask his dismay. "No, honestly, 'course not – go."

"No, 'cause I could stay-"

"No-"

"I mean, we've got plans…"

"Just pizza…" Craig found that he was slapping a pamphlet against his open hand and tossed it over his shoulder with a shrug.

"Yeah, just pizza…" She was hesitating, he was sure – was she hesitating? He realized he was holding his breath and released it with a sigh. "Right. I'm going."

"All right then. Well, um…I'll see you soon." She had picked up her coat now – and did he sound too keen?

"Yeah."

"All right – and…give me a call, and…I hope everything's O.K…"

"Thanks – sorry." There was genuine regret in her eyes as she pulled the door closed behind her; Craig opened his mouth, but whatever he intended to say – and he told himself he didn't know – died in his throat, and then she was gone.

Out in the hall, Sophie could still feel the guilt tugging at her, a fidgety weight on her conscience as the door clicked shut. She leaned her head back against the door with a sigh, but as she made to move towards the front door, a crash rumbled from the top of the staircase and she glanced up in alarm. For a second, she could have sworn she saw the outline of a man watching her, reflected in the stained glass of the door, but the momentary glimpse retreated as quickly as it had appeared and she hurried from the house.

Craig was still restlessly pacing his dining room minutes after Sophie had departed. He clicked his tongue, swung his arms, snapped his fingers; he felt cut loose, at a loss for how to occupy himself, and he drifted aimlessly about the room until he came to stand before the fridge, his gaze falling to rest on a photograph as familiar to him by now as the back of his hand: New Year's Day, just the two of them, and she was beaming into the camera, more carefree than he could remember seeing her – just free…

A thought replayed itself relentlessly in his head until he forced himself to voice it aloud, as if he were scolding himself for his own inactivity.

"You should tell her." He shrugged again, with tense shoulders. "Just…just tell her. I love you. I love you…" How could three words mean so much? Such simple words, but somehow, they seemed to stick at the back of his throat and by the time they emerged, they sounded foreign, strange…would she think they sounded strange, coming from him? "Oh, just…" He tried a new tack – casual, offbeat, perhaps? "Hey – I don't know if you knew…" No. Wrong. He groaned in frustration and his head thudded forwards onto the fridge door. Seconds later, though, his heart nearly skipped a beat at the sound of the doorbell buzzing and he caught sight of the set of keys on the kitchen table, distinctive with their fluffy pink pom-pom keyring. "Every time!" he exclaimed, scooping up the keyring and hurrying for the door. The bell pealed again and he swallowed hard. "I love you." Well, he had another chance, and he wouldn't let it slip. "I love you." Perhaps if he repeated it enough times, it would come easier when… "I love you." He was almost at the door now. "I love you." This was it. He threw the door open and the words almost flew from his mouth as he stepped into the doorway. "I love you!"

His heart, which had been accelerating with every step he took closer to the door, gave a little flutter and sank like a capsizing ship at the quizzical looks on the faces of two men who stood on his doorstep.

"Well that's good, 'cause we're your new lodgers," one grinned. He appeared the younger of the two, with a mop of brown hair that fell across his forehead and a lively twinkle in his green eyes. His dress sense struck Craig as somewhat unconventional in the usual sense – a tweed jacket, pressed shirt and bow tie; the second man couldn't have been more different, clad entirely in black, the hood of his rather shabby sweatshirt pulled up over his head, partly concealing his face. The first moved forward, but before Craig could even register his words, the second had reached out and snatched Sophie's keyring from Craig's still-upraised hand.

"See – they still adore me," the second man muttered, raising his head just long enough for Craig to see him wink.

"B-but I only put the advert up today – I didn't…" Craig trailed off – he was sure he had seen the face of that second man before somewhere. "Aren't you some bloke off the telly?"

"Oh, no – no, definitely not," the first man said quickly. "No – you've never seen us before, we're just passing through. Aren't you lucky?" The black-clad man stepped back and was eyeing the upstairs window, and as the light fell on his face, Craig realized where he recognized the features.

"You look like that Prime Minister," he blurted out. "Harold Saxon, wasn't it?" Immediately, he felt if possible even more idiotic than he had already felt – telling a complete stranger that he looked like a dead Prime Minister, even if the resemblance was striking.

"No – absolutely not." The first man shook his head hard. "Distant cousin."

"Cousin's nephew," the second put in.

"Twice…three times removed," the first added. "On his half-uncle's side."

"Right." Craig nodded slowly, closed his mouth – which he realized at that point was still hanging open – and opened it again, but all that emerged was a stutter. "Uh…"

"Not quite young professionals – more sort of…" the younger-looking man began. "Ancient amateurs, perhaps."

"Well, one of us could be," the hooded man smirked. "Amateur, that is." The first man hardly appeared to notice the jibe – almost as if he had expected it – and moved to step around Craig, who hastily shook himself.

"H-hang on – there's only one room," he protested.

"Don't worry, we'll manage," the man breezed. "Here – rent. Is that a lot? Is that enough for two? I can double it, if it's any trouble…I'm never sure, really…" To his surprise, Craig found a paper bag thrust into his hands – where had that come from? – and he opened it cautiously. He was disconcerted to find the bag half-filled with crisp bank notes – but they were genuine, he had little doubt. By the time he had torn his eyes away, the two men had pushed past and were standing in the hallway, eyes fixed on the fizzing lightbulb at the top of the stairs.

"So…you two are…" They turned to face him and he wriggled uncomfortably, averting his eyes. "Flatmates? Well, I mean, obviously flatmates now, but…uh…"

"We're mor-" The hooded man went to answer, but was cut off abruptly.

"Oh, it's complicated."

"Ah – I see." Craig nodded, unable to prevent his eyes from moving from one to the other. "Right, that's fine…absolutely fine…"

"I'm the Doctor, by the way," the brown-haired man said cheerfully, and Craig nearly dropped the paper bag when the Doctor took him by the shoulders and pecked him quickly on each cheek. "That's how we greet each other nowadays, isn't it?" The other man lowered his hood, revealing bleached-white hair and a face rough with stubble. To Craig's relief, he extended his hand and his pale features spread into a winning smile that would have been worthy of any politician – Craig couldn't decide whether it reassured him or only unsettled him further.

"I am th-"

"And this is…" the Doctor interrupted, but then trailed off with a glance at the white-haired man. "He's…"

"Kaiser Stream. Don't mind him – he's just a bit…" His hazel eyes flicked upwards and he beamed as he shook Craig's hand firmly.

"Craig Owens." Kaiser released his hand and slipped Sophie's keys back into his palm; he closed his fingers around them and returned the smile before he could help himself. "Say – how did you know the ad-"

"Who lives upstairs?" the Doctor cut in suddenly. Craig blinked.

"Uh…no-one – I mean, just…someone, some-"

"What does he look like?" the Doctor demanded.

"Just...normal, you know..."

"Really, Doctor," said Kaiser with an exaggerated sigh. "I'm sure Mr. Owens would rather be showing us our room than answering your inane questions. Which way is our room?" He turned his gaze on Craig, and Craig found himself swallowing any objection he might have been about to make, although he nearly choked on it.

"Your room...right, of course, this way..."

He led the way down the corridor that ran alongside the staircase, passing a kitchen, bathroom and his own bedroom, and eventually reaching the vacant bedroom at the back of the house, where he opened the door and stepped back to allow the two men to see inside. Kaiser stepped through first, and if Craig had been able to see his face, he might have noticed that the smile now seemed rather forced. The room appeared comfortable enough - small and plainly furnished with cupboards along one wall, a mirror and small artificial fireplace, and a double bed with bedside tables in the centre of the room - not luxury by a long stretch, but clean and certainly habitable.

"Only one be- ow!" Craig missed the surreptitious movement as Kaiser stepped hard on the Doctor's toe, and there was an uncomfortable pause.

"I'll just…leave you to…ah…discuss it, shall I?" Craig mumbled and slipped out of the room, clicking the door shut after him.

The moment he was gone, the Master rounded on the Doctor, who jumped.

"What?"

"You had to go and say that, didn't you?"

"Say what?"

"'It's complicated'," the Master mimicked.

"Well, it…oh. Right. Yes – well, I didn't mean…" Comprehension dawned on the Doctor's face, but it did little to placate the Master.

"Couldn't you have said we were brothers or something?" he snapped irritably.

"Not really, no – humans, you see, tend to look sort of similar when they're related." The Doctor grinned amicably at the Master's growing impatience and added, "And I could hardly have said we're 'mortal enemies', could I? Nice try, by the way, 'Kaiser'." Now it was the Master's turn to appear baffled.

"Yeah? So what? At least I came up with something."

"It doesn't actually mean Master, you know." The Doctor leaned back against the wall and straightened his bow tie with both hands. Several pleasant images crossed the Master's mind of ways in which the little scrap of material could be used as a deadly weapon; he crossed the room and began patting the bed to hide the twitching at the corners of his mouth. "And as for 'Stream'…brain like yours, I did expect a bit more originality."

"Brain like yours, I'm not at all surprised you lost the TARDIS." Straightening up, the Master raised his hand and watched as the flesh flickered briefly translucent. "Don't suppose there's much chance you'd just let me blast down the door of that upstairs flat and incinerate whoever's in there."

"Your life force is breaking down again already," the Doctor observed, pretending he hadn't heard. "Come on, let's get something to eat – I expect you're starving."

"Finally, something we agree on," the Master muttered, shoving his hands in his pocket and stalking after the Doctor.

In the kitchen, Craig was leaning on the back of the sofa, the pink pom-pom keyring in one hand, absently squeezing it as his eyes lingered on the photograph on the fridge door. The creak of the door jerked him out of his reverie and he tossed the keychain onto the coffee table as Kaiser and the Doctor entered.

"It's perfect," the Doctor announced. "We'll take it. Now – lunch. You're hungry, aren't you, Craig? Can I call you Craig? Yes? Perfect." Craig had hardly had a chance to raise himself from the back of the sofa when the two were already opening the fridge.

"Oh – I haven't got anything in – I'll…" He trailed off – they didn't seem to be listening. "I'll just…watch you eat the bacon, then." Which was, unless he was very much mistaken, exactly what Kaiser had proceeded to do. The Doctor had whipped out a frying pan from a cupboard and was tossing ingredients haphazardly into it, but stopped short, head turned towards the corner of the room.

"Ah – now that would be…dry rot?" Following the Doctor's gaze, Craig found his attention called for the second time that morning to the dark, roughly circular patch on the ceiling.

"Might be mildew, or damp – I'll get someone in," he answered.

"No – I'll fix it," the Doctor said quickly. "I'm good with rot. Call me the Rotmeister…" A violent spluttering sound caused them both to turn.

"'Scuseme?" Kaiser choked through a mouthful of cold ham – had he eaten all the bacon already? "Rotmeister?"

"Well I can't say 'Rotdoktor' – that sounds like a cleaning product. Rotdoktor." The Doctor rolled the word around on his tongue like something he might have eaten in a foreign restaurant. "No, don't call me that. Rot-"

"I'm the Rotmeister," Kaiser interrupted peevishly. "He's the Rotdoktor." With a petulant glare at the Doctor, he returned to the contents of the fridge.

"Whatever," Craig shrugged.

Just watching the Doctor scurrying about the kitchen was making him feel twitchy, so he settled himself on the sofa and waited.

"Who's the girl on the fridge?" the Doctor called out.

"Sophie." Craig couldn't help turning to glance once more at the photograph. "Friend."

"Girlfriend?" Kaiser put in, opening and closing cupboards loudly.

"Friend who's a girl." Craig tried to adopt a light, nonchalant tone. "There's…nothing…going on."

"Completely normal, works for me," said the Doctor over the sizzle of the frying pan.

"Yeah – I met her a year ago at the call centre," Craig explained. "Phones were going down, though – boss is using a totally rubbish business model…"

"I suppose they got rid of the Archangel Network," Kaiser mused.

"Yeah – had to redo all the systems, new numbers and everything. Hasn't been the same since – pity, really, it was…oh, sorry," he apologized. "You probably don't want to know – your…fourth cousin, was it? Anyway – Sophie. No – business models." He shook his head, embarrassed. "I know what they should do – I've got a plan all worked out – but…" His shoulders sagged, voice dropping mournfully. "I'm just a phone drone – I can't go running in saying I know best…" With a laugh, he shook his head. "Why am I telling you this? I don't even know you!"

"I've just got one of those faces," the Doctor replied. "People never stop blurting out their plans while I'm around." He winked at Kaiser, who rolled his eyes and picked up a block of cheese that the Doctor had just grated the end off into the frying pan; the Doctor snatched it back. "Where's the ham gone? No, of course not, should have known…alors, pas de viande…voilà! Omelette du fromage! With a flourish of the spatula, he deftly scooped three light, fluffy golden omelettes out of the pan and onto plates. Kaiser quickly seized one and, using the spatula as a rather unwieldy spoon, began devouring the omelette as though he hadn't eaten for days.

"Steady on, mate!" Craig chuckled, picking up his own plate. "You'll make yourself sick."

"Oh, he'll be fine," the Doctor shrugged. "Something'll appear sooner or later – ought to help. Has helped. Unless he's done something to upset her…" Rather than allow another awkward silence to follow the cryptic statement, Craig hazarded a guess.

"A…doctor?" There was a grating squeal of metal on ceramic as Kaiser viciously bisected his last piece of omelette with the spatula.

"I don't need a doctor."