A/N: The previous parts to this are Weeds and Pains. Must be read!

So, we're back into this! And LBZIP you're so right, gardening is dangerous. This is why I never helped my mum in the garden when I was younger.

Part One

Someone was singing. A beautiful yet haunting melody, seemingly reverberating right inside the Doctor's brain. He eased open his eyes, ever so slowly, and met a familiar bright, blurry world.

He struggled to focus, blinking rapidly until his vision had a little bit more clarity and he saw the vague figure of Rose, lying next to him covered in blood.

"Rose," he gasped, squeezing his eyes shut and opening them again to focus even more...

Her body had suddenly disappeared.

"No, no, no!" he cried, scrambling to his feet. "Rose!"

He looked up, and saw a vague shape lying down the corridor...

"Rose!"

He began to move, his bare feet padding down the corridor towards her unmoving form – but the closer and closer he got, the further she seemed to be moving away...

"Doctor..."

The Doctor snapped to attention immediately, recognising the voice anywhere. "Rose?"

"Wake up!"

The Doctor frowned, looking around the empty corridor for her. "I'm here!"

"Help me..."

"Where are you? Find me!" he yelled.

"It hurts..." she whispered in his ear, making him spin around on the spot to meet no one.

"Please," the Doctor gasped to the ceiling, not even sure who he was talking to. "Let me help her, please let me help her..."

Suddenly the entire world flashed and the Doctor found himself lying on the floor...

"Rose!" he yelled, or at least, half-yelled, as he realised halfway through his voice wasn't right...

His eyes dropped down to his arm, absolutely covered in blisters. He was in Rose's body.

His head snapped up, blonde hair falling in front of his face. He quickly pushed it back and saw his own body lying next to him, a body lying prone and unmoving.

"Rose!" he tried again, trying to push his body's arm, but he couldn't seem to be able to reach. "Are you in there?"

"Where am I!?" it was her again, but he had no idea where the voice was coming from...

"Can you hear me?"

"Yeah, Doctor, please!" she cried.

"It's the Heart, it's messing with us!" he yelled back. "Just stay calm!"

"Stop saying stuff like he would!"

"What?"

"Go away!"

The world suddenly flashed again, making the Doctor snap his eyes shut once more. When he opened them, he found himself standing in the corridor, Rose's unconscious form lying at the end of the hall. He took a step, but it almost seemed like a slow-motion step. He heard a reverberating sound of something like a 'squelch', and he looked down in slow-motion to see his foot had stepped into a puddle of blood.

Ahead of him were his own footprints leading to Rose. Footprints made of blood.

The world flashed again before he could do anything about it, and suddenly he was looking down at his own chest. His ribs were moving, jolting with every beat of his hearts. They were jolting quite hard, actually, and the movement was getting harder, harsher, his ribs beginning to bulge out now with every thumping beat...

The skin broke, and the ribs burst out through his skin. He yelled in horror, but somehow the ribs were coming out even harder now...

Then his ribs broke completely, severing right down the centre.

He thrust his hand out, and out dropped his left heart, right into his palm in a neat plop. But it continued to beat ferociously in his hand as green veins started climbing around it and his hand, the heart pumping faster and faster...

"Doctor!" Rose shrieked, snapping her eyes open. She was back in the corridor, the Doctor's body lying next to her. She reached out desperately for him, but somehow despite being a foot away he was out of reach...

Then he started to change colour. First green, then purple, then rotten black. By the time she could smell it she realised that he was decomposing at 100 times speed. His eyes bulged and his tongue swelled and as the smell reached her nostrils and she snapped her eyes shut, the image burned inside her very eyelids. She kept them firmly closed, tears cascading down her cheeks...

She knew it was continuing in front of her, as a small rip sounded. But she kept her eyes closed, crying and gasping in fear and horror...

"Rose..."

"Doctor!" she cried, and the world flashed again.

They were standing in front of each other in the corridor, their eyes fixed to each other

"It's the Heart, just stay calm," he said gently.

"It doesn't make sense," she sobbed, her eyes still filled with tears.

"I know, hopefully it'll stabilise soon. But none of this is real, just remember that."

She ran forward to him, wrapping her arms around him to cling on tightly, clearly desperate for some sort of protection.

"Don't let go," she begged.

"Never," he whispered, holding her close.

The world flashed again and once more the Doctor was lying on the floor, but this time his hand was in Rose's. He stayed still for a few moments, wondering what horror was going to happen now – but nothing seemed to.

"Rose?" he asked, and didn't get a response. Keeping his hand in hers he crawled to her, turning her over.

He still couldn't see properly, but he could see enough. She was incredibly pale, and had blood on her head and her shirt. Her left eye was bruised and swollen too. He checked the damage, but was quickly distracted when he saw her arm – blistered so badly that it didn't even look like an arm. It looked like some creature had stuck their arm in place of hers...

"You're still poisoned," he realised in a croak.

"Doctor..." a moan suddenly came from her lips, her one working eye opening to look up at him, filled with tears and pain.

"It's okay," he said gently, brushing back her hair from her face.

"I'm sorry..."

"Don't worry. Just relax. I'm going to look after you," he said softly.

"Okay," she whispered.

"Just trust me."

"I do," she croaked truthfully.

He nodded, still not letting go of her hand. "You've barely got an hour. We're going right to the Heart."

Rose frowned. "You can't. It's impossible... you said..."

"I say a lot of things," he said disparagingly, waving a hand. "Besides, nothing's impossible. Just a bit unlikely."

It was agonising, every step he took.

He had patched up the worst of Rose's wounds with pieces of his shirt, and was now carrying her in both arms down yet another corridor. His leg was the main cause of his discomfort, and there was absolutely nothing he could do about it. Frankly, he didn't care. They had to get to the Heart, and he wouldn't get there moaning and groaning about his quite savagely painful, disabling, split open, crushed up, bleeding, destroyed...

He quickly shook his head, trying desperately to keep any thoughts of pain out of his head. He had to get rid of the weeds, and save Rose. No matter how much pain that took...

Suddenly a slim, brunette woman who happened to be completely naked appeared, stopping at the end of the corridor. Then she looked towards him, her eyes widened, and she ran straight to him with everything bobbing around, her hand pointing out to him.

"Doctor!" she cried as she neared. "Oh, I've been looking for you for ages!"

The Doctor's eyes boggled, trying not to look at the fact she was completely naked. "Who are..."

"It's got into my Heart, Theta!" she sobbed out, wide-eyed and panicked.

"Tardis?" the Doctor realised and questioned at the same time with a stupefied expression on his face. He was now far beyond the realms of confused.

"Well, duh!" the TARDIS responded rudely.

"Look, I can't... Just get some clothes on, Tardis!" the Doctor demanded, snapping his eyes shut.

"Priorities!" the TARDIS insisted.

"That's a priority!"

"So you're happy to walk around naked but I can't!?"

The Doctor frowned. "I'm not..." He looked down at himself. "What? Did you take off my clothes!?"

The TARDIS was staring at him too, now. "I'm sorry!"

"Look, look, just calm down," the Doctor said quickly to her, lying Rose gently down on the floor. He was really hoping she wouldn't wake up now. "Breathe. In, out, in, out."

She did, and within seconds their clothes reappeared. "I'm sorry!" she squeaked.

"It's okay, thank you," the Doctor said quickly. "You said the weeds are in your Heart?"

"Please, Theta, please, it hurts," she sobbed.

"I'm trying to get there. I'll get them out, Tardis."

She grabbed his hand, his entire arm surging gold as all his pain numbing as she began to pull him down the corridor. "I'll make a shortcut!"

"No!" the Doctor stopped, yanking her to a halt. "Rose!"

"She's coming too!" the TARDIS insisted, and dragged him off again. They ran down the perfectly straight corridor, a speck of gold seemingly getting bigger and bigger as they ran towards it...

And passed right through.

And suddenly the Doctor was falling. Well, it felt like falling, anyway. He was definitely falling, but he couldn't quite figure out if he was falling down, sideways, or even up. By the time he hit the ground – or was that the ceiling – his head was fully scrambled.

He sat up, to find the TARDIS looking down at him, hand over her mouth in an 'oops' motion. His vision was absolutely perfect, and his hand and leg weren't hurting any more... But he still had no idea where they'd ended up. It was a large, dark room, piled high with junk with mirrors all around the edge.

"This isn't the Cloister Room," he said, but not first the first time that day was very surprised as to what came out of his mouth. His voice was high-pitched...

"I'm so sorry!" the TARDIS whined.

The Doctor frowned. "Sorry for..."

"Doctor! Why are you... Wait, why am I tiny?"

He looked up to find Rose standing there, or at least, he assumed it was her. It was a little girl, around two or three years old, peroxide blonde hair and her shirt acting like a dress with her trousers in a puddle by her feet. She was looking down at herself, checking her hands...

"My hands are so little!" she gasped, and looked back up at him. "And you!"

He looked down at his own, the left one completely healed. His fingers were tiny, but all the same, he ran them up through his hair, his dexterity leaving much to be desired.

He looked around for a reflective surface, and found one in the wall. He went to it – his legs really struggling to move independently of each other – and stared at himself in the reflection.

"I'm little!" he exclaimed, staring at himself. His big brown eyes were set in a tiny smooth, slightly podgy face, and his big brown hair was absolutely massive on his little head.

"So am I!" Rose shouted, running over to him. "What happened?"

"Bet I know," the Doctor muttered, turning to the TARDIS. "Can you fix this?"

"I'm sorry!" the TARDIS practically squeaked. "I don't know what I did!"

"Who are you talking to?" Rose asked, looking vaguely around the area he was staring at.

"Can't you see her?" he wondered, frowning.

"Who?"

"You?" the TARDIS asked, confused.

"Her!" the Doctor said, pointing at the TARDIS.

The TARDIS jumped. "Me?"

"Yes, you!" the Doctor clarified.

Rose slipped her hand into his again, little stubby fingers in his own. "Are you hallucinating? There's no one there."

"Theta!" the TARDIS shouted, having suddenly teleported herself over the other side of the room, spinning around madly. "I can't concentrate, it's got into my..."

She suddenly doubled over with her hand clutched to her chest, crying out in pain.

"Tardis!?" he shouted in alarm, running over to her.

"Oh, Theta, it hurts, please help!" she gasped.

The Doctor looked back at Rose, and she could see he was clearly alarmed. "We have to get to the Cloister Room."

"It's this way!" the TARDIS shouted, staggering upright and running for the door. But the Doctor didn't move.

"You really can't see or hear her?" he asked Rose, wide-eyed.

She shook her head. "No... Bad?"

His expression darkened slightly. "This is worse than I thought."

Rose suddenly burst out into giggles, gazing at his face. "Sorry!" she said when she managed to get it under control. "Your serious face is so cute on a kid! Sorry, what?"

The Doctor rolled his eyes. "The weeds got into the Heart, I know."

"How d'you know?"

"Because she's... Look, it's just a theory at this point, but maybe this weed has grown so big... it's actually become sentient?"

"That's mad."

"Maybe."

"So the girl you're seeing definitely isn't the Tardis, then?"

"I don't know, but if the weed has got into her Heart, which I really think it has, and it's developed an intelligence... it can use images to draw us in. It's... excuse the pun, child's play."

"So all those weird things in the corridor where we fell... That was it just tryin' to faze us?" she theorised.

"Maybe... Or maybe that was the Tardis screaming for help..." He began to run a tiny hand through his still shockingly huge hair. "Maybe it's a mesh of the two. Maybe..."

"... They're entwined in each other and we can't tell what's what any more," Rose finished quietly.

He nodded, just once as he dropped his hand again. "Exactly. But the Tardis would try to help us. I know she would."

"So we figure out if this one's bad."

"Yep."

"Well... Being children isn't helpful," Rose pointed out. "But... s'not exactly that bad either? I mean, we've still got our heads."

He didn't answer that, just gazing at her.

"What?" she asked seriously. "So it made us short. Why did the weed do that?"

"For the same reason we use a knife at dinner?"

It took her a few seconds to process that, before her eyes shot wide open as it hit her in a cold wave of realisation... "Easier to swallow..."

"Exactly."

Rose quickly shook her head. "No, wait. We've been un-aged, de-aged, whatever you wanna call it, and that means all our injuries are gone. We're healthy again. That's good, yeah?"

"I... did not think of that," the Doctor confessed, his brow furrowed slightly.

"Square one," she surmised.

"Yep," he replied, popping the 'p'.

"So what do we do?"

The Doctor swallowed. "... Follow her."

"Sure?"

"No, but I don't think we've got much choice."

She held his hand tighter, and he squeezed back. Then, together, they moved forward. Until, the Doctor suddenly lost Rose's hand as he heard a thump. He looked back at her, only to find her on the floor, clearly having just fell over her massive adult shirt.

She sat up holding her knee, her eyes shining with unfallen tears...

"No, no," the Doctor said quickly, going back to her. "Come on."

"Sorry, I think it's a reflex!" Rose said, wiping at her eyes and getting back up again on unsteady feet.

"Stop being silly!" the Doctor shouted.

"You're silly!" Rose yelled back.

"Well, you're a stinky girl!"

"Well you're a smelly boy!"

They stopped, realising what had just happened.

"We're losing it," Rose muttered.

"Yeah..."