Title: Cosmology

Genre: General, Romance, Character Study

Words: 3,324

Summary: The Doctor finds Rose something that will aid them on their travels. NineRose. Complete.

Disclaimer: Couldn't be less mine if I tried. Even if Christopher Eccleston and Billie Piper have left the show.

Author's Note: Written for the challenge on Lj comm hearts-in-time – Turn a romantic situation between Rose and Nine into a mundane one. A mini-story thing. Oh, and for anyone who's interested, HIT will be getting all my Nine/Rose stuff first :P And the rest of it.

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Cosmology

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It wasn't usual that they ever spent time in markets. In fact, so far as Rose could tell, the Doctor seemed to avoid them at all costs. On the rare occasions when the stopped back in London, he always made a point of refusing to come out shopping with her. In fact, he barely ever ventured out of the TARDIS unless he had to. Any shopping she ever found herself doing, be it clothes, jewellery, shoes and – on occasion – groceries, was done solely in her own company. Even when the Doctor did venture outside into the world of the customer, it was rare. She had once known him to disappear off to Tesco late one Earth night and return not twenty minutes later with corned beef and a tin of spam.

"It'll be the last time you ever complain about my cooking," he'd told her pointedly, scooping the beef out onto the plate like cat food.

He had been right.

The point still stood that the Doctor and shopping were not a match made anywhere. They just didn't go together. It would be like mixing aeroplanes and sea anemones.

So Rose was doubly surprised when, after asking the Doctor where they were headed this time around, he looked up from the controls with devilish glee, face golden in the humming light, and told her one of his favourite marketplaces in the universe.

They walked out onto amber pavements and beautiful crimson skies. The TARDIS was parked slap bang in the middle of a cobbled street, busy tourists spreading as far as Rose could see. The air, cooler than Earth air, made her have to wrap her mauve scarf around her neck again for comfort as she peered between the people on the street.

The TARDIS door clicked shut behind them.

The Doctor, after offering her a brief grin, began striding purposefully between the crowds. Rose, fearful of getting swept up by the current of shoppers, trotted hurriedly after him.

"Where're we going?" she asked as she caught up, wind blowing gently in her face.

He shot her a sideways look, somewhere between a smirk and a frown.

"There's a stall 'round here I think'll be quite useful to us," the Doctor explained, weaving between the masses of heavy bodies to the outskirts of the square. "Come on."

They managed to work their way down the side of the cobbled square, lined with tables and stalls that sold all sorts of beautiful products. Rose was instantly entranced by a stall which was home to different sized spheres of metal, all glowing and humming their own tune. She smiled at the seller, then reached a delicate finger out towards one of the smaller, silvery balls. The emerald lights encrusted around its circumference seemed to grow a little bit bright with the promise of her touch, and a hazy golden light began to glow around the outside.

Rose, spellbound, spread her palm over the sphere, not touching, but making the shape with her fingers. It was so beautiful, singing to her in that gentle hum, almost electronic but not quite. Almost alive.

Until a hand on her wrist snapped her out of her daze. She turned to find the Doctor looking at her sternly.

"Wouldn't if I were you," he advised, releasing her wrist but holding her eye contact. He explained before she could ask. "'Rocks of Neptune'. They're collector's items." He was careful to lead her away from the stall across to velvet grass to another square as he continued. "If you're clever they can be used like instruments. Each one produces a distinct sound, no other one like it. Every one is unique. You can build up a collection that makes the most beautiful, captivating music that will never be the same more than once in a row."

Rose cast a glance over her shoulder longingly.

"They sound beautiful…"

The Doctor raised an eyebrow sceptically. "Think of it like the Sirens' song. They lured sailors to their deaths on jagged rocks by singing to them, right? Same sort of thing with those. Touch one with your bare skin, you're doomed to a lifetime of following the music around 'til it leads you to your death. Risky thing, going into Neptune's stuff. You'd be better off with a recorder."

"Okay, maybe not so beautiful," Rose laughed as they neared the end of the lawn to a quieter, less hassled part of the town.

"Oh, as beautiful as they come. But deadly. You want to be careful with things of beauty; they'll lead you astray."

Rose bit her bottom lip playfully catching his eye. "You sound like you're speaking from experience," she half teased.

The Doctor shrugged and said nothing.

They passed one or two other stalls with things of little interest. One actually looked like someone had just gone around collecting junk off the floor and shoved it on a table to sell. Another had pyramids of what looked like sugar cubes. There were quite a few, too, that were completely empty, about five or six all bunched together. At first, Rose thought it was some sort of scam with "invisible trinkets" – until the Doctor pointed out a sign that said 'Tables for Sale' and she suddenly became very interested with the fingernails on her left hand.

They were walking under a tunnelled part of the market, a light material draped over the street like the sort of material tie-dye clothes were made from. It was darker here, but a little warmer. Less busy, too, which Rose appreciated, because it meant she had time to gaze at all the alien ornaments as they passed. The Doctor groaned impatiently when she insisted on stopping at every other stall, eventually lowering himself to tugging on her sleeve like an impatient child.

"If you didn't want me to shop, why bring me to a market?" Roe pointed out while he was hovering awkwardly at her elbow. She gave the sales person a friendly look, but found she wasn't quite sure where to smile at – there were no defining features on the alien at all. Just a… blob. She picked at the headbands on the desk, surprised to find something so human in a place so alien.

"I didn't bring you to a market," the Doctor retorted, watching her suspiciously. "For one thing, you don't have any money. Did it not occur to you that I might need to pick something up? And that you've been holding me up with all your pit-stops?"

Rose gave him a sheepish looked and winced, placing the headband back down on the table.

"Sorry," she mumbled.

The Doctor folded his arms. "No, no, you carry on as you are. We've probably missed what I wanted to find, anyway."

Despite his protests, they left the shop not a few minutes later. They walked together through the dwindling crowd, Rose gazing at the passing tables and ornaments but no longer stopping every time she felt drawn to something.

"So, where are we?" she asked after a few moments' silence, feeling it weigh down upon her.

The Doctor slipped his hand inside his pockets as he walked on, watching Rose from the corner of his eye.

"This is the market of Qu," he answered, gesturing abstractly with his head. "One of the busiest times of the year. If you'd come back here in a week, this would all be just empty cobbles and grass. No one here. And this is the year one of my favourite stalls is around. Not to mention useful. He's a time hopper himself – doesn't stick around in one place too long. There are other places to get to, after all."

"Right." Rose sounded a little unsure so, for good measure, the Doctor turned and smiled at her.

"Don't worry – we probably haven't missed him. Though it's a bit difficult to track him down again if we have. Fingers crossed, yeah?"

Not waiting for an answer, he strode on ahead, arms swinging by his side as he commanded his way through the canopy. The Doctor came to a stop at a particularly shaded corner near the end of the canopy, hidden away between folds of the tent. This stall, cast into shadow, was completely empty. A figure sat slumped on a stool, wrapped in indigo blankets like saddlecloth, but everyone else passed the table by like they couldn't even see it. A pure black mass of swirling… something… seemed to peer out from tiny openings in the cloak, and Rose felt like she was looking in on a universe.

The Doctor gave Rose a small nudge in the ribs. "Haven't missed him. I'm pleased about that, his stuff's hard to come by."

The table itself was smaller than the other tables, and more rickety, balanced by a rock under one of its legs. It was also empty, aside from a small wooden box in the centre, like a perfectly square treasure box.

Rose watched with interest as the Doctor took a moment to gaze at it, before meeting the eye of the seller and grinning.

"May I?" he asked, hovering his fingers over the lid.

The figure gave a tight nod, the cloth rustling with the movement.

Grinning, the Doctor peeled open the lid of the box. Then, quite to Rose's surprise, he stepped back, instead manoeuvring a hand to offer her a look. She gave him a question frown and he nodded.

She stepped forward.

What she saw was hardly very impressive. An empty box. That was it? He had come all this way for a box? Then she glanced at him and knew he was up to something – he wouldn't waste his time out here. Rose looked up to smile at the creature sitting on the stool, only to find there wasn't much to smile at. Just a pile of cloth.

"They're a bit reclusive," said the Doctor by her side, following her gaze with his. "Don't talk much. Or communicate. They're traders, going from place to place with their little boxes. Great friends of my people." A muscle twitched in his jaw a moment as his eyes became glassy. "Don't suppose there's many of them left now."

Rose looked to him sympathetically, lowering her voice.

"So... this box..."

"Right. Yeah." He turned to her with a bright grin, his eyes back to their natural tone. "There's nothing much in it for the Revellers, really. They just get to see the universe, spread themselves out a bit. Not much else for them to do. Anyway – you know the TARDIS is bigger on the inside than the outside?"

"Might have cropped up," Rose responded quietly. If the Doctor heard her, he ignored it.

"Well, this – " he pointed admiringly to the box – "is sort of a little piece of home. We leant them a small piece of our technology, hundreds of millennia ago. This little box here can hold more than is in most planets in this galaxy. There are hundreds of things in there, all waiting to be picked."

Rose shot the box a dubious glance. "...Picked?" she questioned, images of apple trees springing to her mind.

"Well, think of it this way. All these different people on different planets. They find a Reveller who's in the trade and swap something. Take something from the box, and donate something to it. You can donate for free if you like, as I've done in the past – but this time, there's something in here I think you might like. Go on, take a look."

"Doctor, I looked before – "

"You didn't know what it was, though," he interrupted with absolute patience. "Trust me."

So, wondering just what is was she would see, Rose leaned forward and took another look into the shallow box.

Except that it wasn't shallow.

It was a writhing mass of swirling black matter. She might have called it liquid, except it was spinning like a tornado, yet somehow remaining thick like molasses. She felt a warm breeze, saw streaks of colour dotted inside and abyss of the impossible. Then, trusting instinct, she slowly reached a hand inside the depths and let her fingers spider their way around. It was like putting her hand into a cold river, a volcano and a hurricane all at once. She gasped with the strange tingling sensation that came with it and felt the Doctor grin. Then her eyes widened and she turned her head, staring at the Doctor.

Because he was grinning – and there was no way she could have known that.

His eyebrows quirked upwards. "Good, eh? Now, I think the thing you'll be looking for is right about... there..."

Her fingers suddenly brushed against something cool and smooth, something much more solid than the abstract... whatever it was... surrounding her hand. She pulled it out and turned her palm upwards, seeing what lay in it.

A stone. A rich pink stone, bruised with purple and fused with a strange aura that Rose couldn't quite make out. It was about the size of a grape, but uneven in shape. It was weighted but not heavy, glowing but not light, beautiful yet strangely mundane. She couldn't take her eyes off it. It was only when the Doctor took stone from her hand between his thumb and forefinger did she snap back to reality.

He held it up as a jeweller would hold a diamond up to the light. Then he grinned almost sardonically and flicked a small ring at the top, no more then a couple of millimetres. It jingled pleasantly. His eyes flicked to meet Rose's and he was pleased to find her smiling.

"Got any gum?"

It took a moment or two for the question to register, and she wasn't sure if she'd heard him right.

"Excuse me?"

"Gum," the Doctor repeated, but did not elaborate.

"Like... chewing gum?"

"Exactly like, yeah. Got any on you?"

"Uh..."

Rose rumbled in the pockets of her black jacket, finally pulling out a rather bedraggled packet that she feared might have not survived the washing machine. She handed it to the Doctor and he slid the stone back into her palm. Instantly she felt that strange sensation wash over her again, like everything around her was its contradiction in terms and yet somehow made sense. It was very strange.

It was then that she noticed the Doctor holding the discoloured packet of half–eaten chewing gum over the open box and letting it drop in, like it meant nothing.

She frowned at him incredulously.

"Doctor!" she admonished loudly, instantly going to the box's edge to open the lid again and find it. Rude was one thing, but to use the box as a rubbish bin? That was crossing a line.

However, she was stopped by the small creature, a voice which she didn't quite hear but somehow knew anyway, like it was carried on the wind.

"One – gift – only."

She looked up with wide eyes, hand paused over the lid. The Doctor looked on amusedly.

"One man's trash, Rose," he said slowly and she turned to him disbelievingly.

"You what?"

He shrugged. "Somewhere out in the universe, someone is going to find incredible use for that. Sure, to humans, ut may be a minty, rubbery substance that lasts half an hour or so. But to someone else, that's a meal to last a lifetime, right there. Could save someone's life, that. For example, it's got all the nutrients a Flyke would need to survive. Besides – " he made a gesture to the stone in Rose's hand – "where d'you think that came from? I know a place that's teeming with elements like that. Well, not exactly like that. That one's faulty."

Rose gazed down to the stone shimmering in her hand. "Faulty?" she echoed, unconvinced. To her, it looked perfect.

The Doctor nodded a goodbye to the Reveller and directed Rose back the way they had come. His work was done now.

"Yup. Got mixed up with a bit of radioactive ion residue. That, and it's been knocking about in that box for god knows how long. Its chemical structure has altered, just slightly. And once we get back to the TARDIS, I can alter it some more. Then it'll be as useful to us as the TARDIS key."

"Why's that?" Rose asked, feeling happiness spread through her like winter sunshine. She couldn't help grinning as they made their way back.

Neither could the Doctor.

"You'll see."

I–I–I

"Oi, Rose – catch."

She was sat on the edge of the controls, legs swinging idly as she waited for the Doctor to finish his work on the stone. Pocketing the sonic screwdriver, he chucked it back to her as if it meant nothing, then pointed to the top, the small ring attached to it.

"Pendant," he said, as if that explained everything, then folded his arms and leant against the console next to her.

Rose felt the stone grow warm in her hand, comforting, like a bath when it's the one thing you want.

At his word, she automatically reached for the plain chain she was wearing, unfastening it and threading it into the ring of the stone. It was indeed a pendant, and as she did the necklace back up again, she found the stone weighed just perfectly to be comfortable.

Turning to the Doctor, she beamed. "So you took me all the way out to a marketplace just to get me some jewellery?"

He snorted and shook his head incredulously. "As if. Nah, I needed the chemical balancing of that particular stone so I could offset the ionic structure with my sonic screwdriver. Combine it with a bit of jiggery–pokery, hocus–pocus and bob's–your–uncle, and you've got yourself a Doctor sensor."

"A what?" Rose asked, half with a laugh, half with complete confusion.

He chuckled. "A Doctor sensor!" he enthused. When Rose stared at him, mouth open slightly in a small smirk, he rolled his eyes. "Look – you know how the TARDIS key can sense the vortex if it needs to? Gets hot? Well, that little stone there will sense me. With all the messes we get ourselves into, it'd be useful for you to know if I was around or not."

Rose fingered the pendant with a wry smile, not quite believing what she was hearing. The Doctor unfolded his arms and pushed himself off the console, squinting up to the ceiling for a moment as if he were looking for cobwebs.

"What about a Rose sensor?" Rose suggested, watching him. His eyes came to hers again and she found herself blushing, looking away. "You know. For me."

"Got one." He tapped his head meaningfully. "I know when you're around. Mostly 'cause I usually have a headache when you are."

She slid off the console, giving him a slap in his shoulder. They laughed good–naturedly and Rose felt comforted by the warm feeling in her chest.

"So, this stone – what's it called, then?"

The Doctor roamed around the room, not quite looking at her, already falling back into work mode as he decided their next destination.

"Oh, lots of names. Depends where you go. Tell you what, though, want to know something funny?"

"What's that?"

"Its cousin is actually common on your planet. Found all over the place – if you know where to look. Tell you what, though, it's a bit weird now I think about it."

She sidled up to him, peering at the codes flitting across the screen.

"Think about what?" Rose asked distractedly, trying to make sense of the complicated symbols.

The Doctor pushed a button and flicked a small switch under his thumb, moving around the console again as the central column began to glow with the beginnings of life.

"The name of it, on your planet." The Doctor looked up, eyes meeting hers with a content grin. "'S called 'rose agate'. Funny that."