Burning. The world was burning. The Doctor snarled, his brow slick with sweat, moaning and tossing in his sleep. His body was knotted in the thin sheets, his hair falling in front of his eyes.

"Martha!" he screamed, thrashing and turning in his sleep. "Martha!" Where was she, why didn't she come running? He began to sob, his hands raking through his hair. "Martha!" His eyes snapped open and he shuddered. The room was baking hot; his healing wounds were itching horribly. He groaned.

"Martha," he rasped, his head sagging down into the soft pillow. He jerked as he heard soft footsteps sounding down the corridors. And she was there, wearing a clean pair of jeans and a simple cotton top, smiling gently.

"Hey," she whispered, coming in and sitting on the end of his bed. She took his hand, fondling his fingers gently. "How are you?" He looked up at her blearily, his chest heaving.

"It hurts," he said heavily. She sighed.

"I love you," she exhaled. He tried to sit up in his bed, breathing raggedly.

"I love you too."

"NO!" Martha jerked awake. She could hear her panting breathing echoing around her. "No! Thick, thick, thick, thick, thick!" What the hell was she thinking? She was all out and ready to sort things out for herself then BAM! This killer had outwitted her again.

She looked around her and saw nothing but black. Getting to her feet, Martha pressed her hand against the wall she had just been leaning on. It was rough and curved. She followed the curve around and soon came to a hunk of splintering wood. A door. Locked, of course. She carried on. The room seemed to be going round in a circle. Just as Martha thought she was back to where she started, she stumbled on something. Something soft.

"Ow!"

"Oof!"

"Who is it?" said Martha in a quavering voice. "I'm Martha."

"Oh God," whispered a female voice. "Martha."

"Mrs Lankinson?" Martha started, stepping back. She fished her phone from her pocket and the light illuminated the tear stained face of her landlady.

"There was this thing," she whimpered. "This shadow…"

"What are you?" Martha asked warily.

"What do you what am I?" the woman wailed. "I'm me?"

"I don't trust you," said Martha. "How do I know you're not possessed or something?"

"How do I know you're not possessed," sniffed the woman. "I was ambushed by this shadow and I woke up here and I had these dreams… and there are others…"

"Others," said Martha, edging away slightly.

"Mmm. There's this boy, and animals, lots of animals. A cat. Lots of birds."

"Where?"

"Here and there," she said. "In other rooms. Sometimes we have to go up to the top and it straps us down and takes our blood and it makes us sleep and I wake up here alone."

"It?"

"The shadow."

"What's that supposed to mean?" Martha shouted. She composed herself. "You have to tell me."

"I thought you didn't trust me," Mrs Lankinson said quietly.

"I don't," Martha calmly replied. "Why don't you try and make me trust you, hey? Please. I need to get back to the Doctor, he's hurt."

"What?"

"You heard," said Martha forcefully. Inside she felt like crying. But she clenched her fists and ignored the weak part of her mind. "Why did you bring me here?"

"I didn't bring you here! I've been locked here for hours!"

"You tried to kill me," said Martha slowly. "You tried to kill me in your house and then you injected me with something and I woke up in here."

"I swear I never… I heard a noise, in my house. Behind the curtains. It jumped out at me… pain… in my head."

"You said something about dreams," said Martha. "What does that mean?"

"Hazy… I dreamt about… you…your face, choking, then your… friend the Doctor… then Portland bill, I dreamt about Portland bill."

"Portland bill? What's that?"

"Martha please…"

"You have to help me," said Martha. "Please. I have to get back to him. He won't know where I am."

"Portland bill is on the coast, five minute drive from my house. It has a lighthouse… a tacky little gift shop."

"A lighthouse? The Doctor said the TARDIS was parked by a lighthouse. Mrs L, Portland bill is the only lighthouse on the island, right?"

"Mmm. What of it?"

"Don't you see?" Martha rubbed her hand against the rough wall again. "We're in the lighthouse. This room is a complete circle. This door leads to the stairs I guess. So the TARDIS is out there…don't you see?"

"I suppose," said Mrs Lankinson. "But that doesn't really help us get out. We're stuck here."

"No," said Martha firmly. "We'll sort it out. Mrs L, how would you describe the shadow you said attacked you."

"I don't know…I…"

"It's really important!"

"I don't know!" the old woman screamed. " It was only a shadow, I couldn't…. I just don't know." Martha sighed and sat down, tapping her phone on her knee anxiously. Sniffing, Mrs Lankinson gestured to the mobile. "Why don't you call him on that?"

"No signal," said Martha.

"No signal?"

"None. Zero bars."

"So what do you suggest we do now?"

"All we can do is wait."

!

!

She was sitting differently to the way she usually sat. She was poised rigidly, her back straight, her chin stuck out defiantly. Not relaxed or at ease at all. Her hair was arranged differently to usual as well. Her fringe was slightly fuller than usual, sweeping in front of her eye. He wasn't sure he liked it.

"How long have I been out of it?" he asked.

"It's gone lunchtime," she said. "I made you something."

"You made me something?" Since when could Martha Jones- despite her best efforts- cook?

"Yeah. Is that okay?"

"Uh, yeah. Just unexpected. Thanks."

"Do you want me to bring it to you?"

"That'd be nice," he assured her. She smiled and walked out the room. No, she almost marched. What was up with her?

Maybe she was ill. Maybe she was feeling the effects of the pregnancy. Maybe she had a stiff back. Maybe… what was the use? He knew what was going on. He just didn't want to think it. Didn't want to say it. But he had to.

"You've been possessed Martha," he husked. "They got you. The killer… oh shit." His hearts jumped in his chest. He leapt up, the sheets covering him crumpling onto the ground. His whole body throbbed. He hissed out a curse.

"Martha," he whispered. "Where are you?" She couldn't be dead. That was the first thought that fluttered through the Doctor's mind. Not after everything. The hospital on the moon, the family, the year, Tom and now… the baby. "I love you. You can't just leave me."

"What's that?" The fake Martha walked in holding a tray of pasta. "Hungry?"

"No," he said shortly. "We have a killer to catch."

"Right," she agreed. "Where are we going?" The Doctor walked into the console of the TARDIS, ignoring her completely. He grabbed his coat and walked out into the midday sunshine.

"You do realise you don't have anything on your feet," she said.

"Yup. We're going… that-a-way."

"This way?" He answered with a jerk of his head as he strode towards the lighthouse. She struggled to catch up with him."

"What are you doing?"

"Now the thing is Miss Martha Jones, the thing is, this is a lighthouse. And around this lighthouse is-" He banged his hand into thin air, and it bounced back. "A force field. And the question is: why? What do you think?"

"I don't…"

"Do you know how to get through?"

"No."

"You use one of these!" He fumbled in his pocket and extracted… a tube of toothpaste. "Uh-uh," he frowned. "Where is it? Where's my sonic screwdriver? I love my sonic screwdriver!"

"Right," she said slowly. "Don't you think we should go and look for the thing." She jerked her head over her shoulder.

"Nope," he said. "Because there is a force field around here and I want to know why. You know that, don't you?" Despite his earnest bluffing, the Doctor had no idea what to do. If this thing had commandeered Martha's body, he needed to look after it- she wouldn't appreciate coming home to a messy house and the same applied to bodies from his experience. However, if this was simply a copy of Martha, and the real Martha was somewhere else, body and all, he frankly didn't care what he did to this thing because it had violated the rights of his favourite person in the world and he was not happy with that.

That was why the fake Martha found herself pinned up against the wall, struggling, as the Doctor leafed inside her one pocket- on her jacket- at extracted his sonic screwdriver. He pulled a hurt face.

"Thief!"

"There it is," she said brightly. He raised his eyebrows. The killer knew she'd been found out. A snarl emitted from Martha's throat and with strength unnatural to a five foot two woman, she threw the Doctor to the floor. He looked up at her, spitting blood from his mouth, his healing wounds throbbing angrily.

"That wasn't very nice," he said. Martha snarled again, and this time she was really angry. The Doctor backed away on his bum, scrambling to his feet cautiously. As he watched the body of Martha Jones seemed to burn before his eyes, her face growing pink, her fists clenching. Then, a ball of fire erupted in her middle and she disintegrated.

Even though the Doctor knew it wasn't really Martha, he still felt faintly sick.

Then, from the pile of ashes at his feet grew something else. His heart leapt in his throat.

"A churzaarg?" He sped round the side of the lighthouse, his elbow banging again the force field every so often. The alien creator snarled and followed him round the smooth curves of the lighthouse. The Doctor yelled as the spiked tail whipped past inches away from his head….

Martha sat up suddenly.

"You hear that?" she whispered. "Screaming…it's the Doctor!"

"That's good isn't it?" asked Mrs Lankinson.

"Well he's alive," said Martha. "But he's screaming." She ran over to the door and rattled handle. "DOCTOR!"

"Martha?" The Doctor heard the shouts. "You're inside the lighthouse!"

Martha spun her head round, looking at the old woman excitedly.

"He can hear me," she gasped. "He's going to save us!" Mrs Lankinson turned to her.

"No, Martha. What about the screaming? He's the one who needs saving, not us." Her grin fading, Martha hurled herself against the door.

"DOCTOR!"