A/N: Just a silly little idea that grew into an alarmingly long not-drabble. This was supposed to be short, honest.

It started innocently enough, so innocuous that Rose hardly noticed the difference.

The Doctor's attention had been absorbed by a small pile of alien technology he'd brought home (against regulations) from Torchwood, when he heard a rather loud hiss of frustration from the other room. "Rose?" He called, slipping his glasses off the bridge of his nose. "Everything alright?"

There a muffled answer, followed by an audible sigh. A moment later, Rose strode into his office, irritation clear in her expression. "This bloody flat is gonna be the death of me."

The Doctor sat up straighter, glancing around for the source of her foul mood. He wouldn't purport to be an authority on the quality of flats, but he thought theirs wasn't too shabby at all: two bedrooms, a cozy sitting room, decent bathroom, and a very quaint little kitchen. They were also just a block away from a wonderful row of little shops. What more could a human need?

Apparently something was lacking, and Rose was in a position to tell him what it was. "What's wrong with it?"

"I can never get a signal here, that's what's wrong!" She tossed her ePhone onto the table. "It's driving me nuts!"

The Doctor picked up the smartphone curiously, slipping his glasses back on. The little differences between this universe and the one they'd come from always surprised him, and her phone was one such example. They were called ePhones rather than iPhones here, but everything else was unchanged: same manufacturer, same operating system, same design. "Bad reception?" He queried, squinting at the screen as he scrolled through the menus.

"Yeah," she said exasperatedly, rubbing at her eyes. "It keeps droppin' calls. My mum thinks I'm avoiding her." Rose caught his smirk, and she slapped at his arm lightly. "Oi! I'm not the one scared of her! That's your job."

"You can say that because she's never tried to slap the life outta you," he replied breezily, setting the mobile down. "Remember when I brought you back home a year late? Thought I was gonna regenerate on the spot, I did."

Rose smiled, her tongue peeking out from between her teeth. The Doctor seemed to always have that effortless ability to make her smile, no matter what body or universe he was in. Her eyes fell onto the mishmash of circuitry he was fiddling with. "Probably pointless to ask if you signed that lot out before taking it from Torchwood?"

The Doctor had the tact to look sheepish. "I might have glanced at some of the paperwork." He paused, wrinkling his nose distastefully. "Well, I say glanced. More like I was aware that there was paperwork. Well, I say aware-"

Rose laughed, cutting him off mid-ramble with another playful slap. "Some things never change," she chided, rolling her eyes. "Just get it back into the lab before anyone notices, yeah?" She reached for her mobile again, dropping a quick kiss on his cheek. "I'm absolutely knackered. You coming to bed soon?"

He nodded, readjusting the glasses perched on his nose. "Almost done here. Leave your mobile. I'll take a look at it."

Rose gave him a dubious look, hesitating.

The Doctor did his best to look reassuring. "Won't break it, I promise."

"All right," she agreed reluctantly. He only had regular screwdrivers and other ordinary tools scattered on the table, so it ought to be fine. "But no cracking it open or anything."

"Wouldn't dream of it," he'd sniffed.

The next morning, Rose had found her phone sitting on the kitchen table, safe and sound next to a cup of tea. She was surprised but delighted to see five signal bars appear in the corner, as opposed to the usual one or two she got while they were at home. It was also receiving a perfect WiFi signal. "How did ya do that?"

The Doctor shrugged, not quite meeting her gaze. "Oh you know, little of this, little of that." He hastily picked up a piece of toast. "Even a dash of human DNA can't water down my brilliance."

Rose narrowed her eyes suspiciously. She'd been with the Doctor long enough to recognize when he was hiding something, and she opened her mouth to call him out on it. "Doctor-"

The shrill ring of her phone made them both jump. Sighing, Rose looked down at the screen. "It's Torchwood. Can't be anything good if they're calling us so early in the morning."

As it turned out, a non-terrestrial spacecraft had been detected in the London airspace. The subsequent crash and clean-up kept both of them and Torchwood quite busy for most of the week. Compared to that, a suspiciously well-functioning smartphone seemed like a paltry concern.

That is, until their toaster caught her attention.

Rose stared at the two pieces of bread that popped up. Vaguely, she thought it was a good thing they'd opted to get a flat separate from her parents; her mother would surely have some choice words ready if she caught her daughter gaping at the toaster, of all things. But Rose felt gaping was a completely justified reaction in this case. Gingerly, she picked up one of the slices of toast. It was perfectly done: lightly browned and crisp throughout. She plucked both pieces from the slots and stuck two more slices of bread in.

Identical results. "Doctor!"

"What? What's wrong?" His familiar, spiky-haired face peered around the wall, a toothbrush poking out from one side of his mouth.

"Look at this." She thrust the toast at him, shaking it accusingly. "Is this your work?"

"Um," his eyes flashed down at the toast, then back up to her face. "It's toast?"

"I know it's toast," Rose said, rolling her eyes. "But look at it. It's not just toast, it's perfect toast. No uneven brownin' or anything. But not only that," She watched his face carefully. "It cooked in two seconds flat."

"Oh." The Doctor looked down, abruptly interested in his feet. Maybe that adjustment had been too much of a give away. "I might have tinkered with it a tiny-"

"Hold on a minute." Rose paused, twisting her head to look about the kitchen. "The fridge," she said slowly, thinking. "It was ice-cold when I opened it last night. The orange juice was frozen solid. And the telly last night...it had more channels than I remember subscribin' for."

The Doctor pulled the toothbrush from his mouth, a guilty look plain on his face. "The internet might be a bit faster, too," he said quietly. "Well, I say a bit-"

"Doctor," Rose interrupted, crossing her arms. "Have you been fiddlin' with the appliances?"

He tried not to look, he really did. But his gaze flickered for a second towards one of the chairs, where his suit jacket was hanging.

Before he could deflect her attention, Rose immediately snatched it up. Her hand plunged into the right-hand pocket, and closed around a familiar-feeling object. She held it up between then, looking at it incredulously. "Did you-"

The Doctor looked guiltily at the sonic screwdriver in her hand. "Well, you see-"

"Please tell me he gave it to you. The other Doctor."

"Oi! It's mine too, if you think about it." He plucked it from her fingers, managing to look indignant.

"So..." Rose didn't quite manage to hide a smirk, unsure if she ought to be annoyed or amused. "You nicked it."

"Borrowed it," he corrected.

"'Borrowed' implies you intend to return it." The smirk turned into a full grin.

"All right, I nicked it. But I left him the spare." The Doctor bit his lip. "Well, I say spare..."

"Doctor?" Rose raised an eyebrow. "What did you do?" Honestly, he was an awful liar.

He sighed, setting his toothbrush down on the table. There were times he almost wished that Rose didn't know him so well. "Well, this one-" he gestured with the sonic screwdriver. "-is the spare."

"Oh." She uncrossed her arms. "So you left him with a working sonic." A muscle in his jaw twitched, and Rose groaned. "Right?"

"Not...exactly." The metacrisis Doctor shrugged. "It's fine, really. Near-perfect working condition. Just like new. Molto bene."

"You're sure?" Rose didn't like the evasive tone he was using. But then again, it's not like they were in any position to return the thing, right?

"Absolutely!" The Doctor grinned, leaning in to give her a quick kiss. She didn't need to know that the other Doctor was stuck with a sonic screwdriver that had a cracked secondary resonator ring. Honestly, it wasn't even that big of a deal: 98% of the settings didn't even rely on that bit. Things might go pear-shaped if he happened to use either setting 10893E or 19999A, though...

He felt concern disturb his thoughts for a minute, but the half-human Doctor dismissed it. The probability that the Time Lord Doctor would need either of those functions was small.

Besides, it's not like a time traveler would need to force apart two opposing bits of time and space or blow out every piece of terrestrial technology in the immediate vicinity on a daily basis, right?

Leadworth, England.

The other universe.

The ship moved with an awful kind of grace through the sky, its crystalline spokes surrounding an enormous, eerie blue eye. It was focusing a beam of concentrated light from its pupil, scrutinizing every bit of the village. It was hard to miss, drawing every person's attention to it. Including Prisoner Zero's.

The Doctor let a small smile stretch his lips, a feeling of triumph rising in him as the Atraxi ship drew closer. "See, that ship up there is scanning this area for non-terrestrial technology." He lifted his right hand, holding an item aloft. "And nothing says non-terrestrial like a sonic screwdriver."

It emitted shrill thrumming sound, and chaos instantly followed. Amy and Rory instinctively ducked as the lamps around the square burst, littering the ground with glass and bits of metal. It was a cacophony of sound as car alarms blared to life and cars honked, making their ear drums ache. Amy couldn't help but look on in half-alarmed amusement when a firetruck suddenly got a mind of its own and drove off. She looked quickly at her boyfriend, who laughed in amazement.

And the Atraxi ship was moving steadily in their direction.

The Doctor's gaze never shifted from Prisoner Zero. "I think someone's going to notice. Don't you?" The screwdriver felt unusually hot in his fingers, but he'd have to deal with that problem later.

The multi-form growled, then barked sharply at him. Still defiant.

The Time Lord didn't flinch, pointing the sonic screwdriver at the nearby cherry-red phone booth. With a crash, the phone inside exploded and panes of glass shattered outwards. He felt almost giddy for half a second.

Then the tool in his hand abruptly seared at his fingers. With a crack of sound, the circuitry burst, showering him with sparks and tiny bits of white-hot metal. Amy and Rory gasped, jumping back and away.

He dropped to the ground, gingerly picking up the charred remains of his beloved screwdriver. "No, no, no, don't do that!" A quick glance over its burnt insides was all he needed to see the cause: the damage had originated in cylinder two, where the secondary resonator ring was housed. It had probably been fractured to begin with, and then gotten worse when he'd fixed the crack in Amelia's wall-

Hold on. A cracked secondary resonator ring? That had been the problem with his first sonic, causing him to switch to the spare. So then why...

His jaw dropped open as the pieces fell into place. "You're kidding me," he mumbled under his breath, standing up straight.

"Look, it's going!" Rory's voice interrupted his rapid-fire thought process.

"No!" The Doctor yelled, watching the spacecraft move away. "Come back, he's here!" He waved uselessly in the multi-form's direction. "Come back! He's here! Prisoner Zero is here!" Obviously, they couldn't hear his voice or see his flailing arms, but the Doctor was too frustrated to care. "Come back! He's here! Prisoner Zero is..." He trailed off, shoulders slumping dejectedly as the Atraxi disappeared from view. "...here."

"Doctor!" Amy rushed forward, pulling at his arm."The drain. It just sort of...melted and went down the drain." She sounded slightly unsure, as if not really believing what her eyes were telling her.

"Well of course it did," he said exasperatedly. What did she expect a multi-form alien to do? Stick around?

She swung around to face him, slightly flustered. "What do we do now?"

"It's hiding in human form," he replied, albeit a little resignedly. His big, brilliant plan and sonic screwdriver dashed to bits and this woman was shouting at him for answers. "We need to drive it into the open." The Doctor found it hard to sound confident, as the list of things that he could use to help them had dwindled down to...well, zero. "No TARDIS, no screwdriver, 17 minutes." He clenched his hands, wracking his brain desperately. "Come on, think. Think!"

Admittedly, he was rather distracted by one persistent thought: if he ever got his hands on that bloody Metacrisis Doctor, he'd slap the remaining Time Lord bits out of him.