A/N: Here's chapter 3! For anyone who is reading THE FINAL BATTLE, Rose is NOT a time lord in this story! The plot line wouldn't work if she was!

Special thanks to XTimeGirlX for beta-ing and everyone who reviewed and added! Thank you!

Chapter 3

One Heart

I'm in Rose's body. This is going to be fun! Wait. If I even touch this body she'll know! Or will she? The Doctor considered this thought for a moment before pinching himself. A slight spark of pain shot through his arm.

Okay, I know that was a stupid idea but you never know! I mean, it's kind of impossible for me to be in THIS body so why should it not be possible for Rose to feel the pain in HER body? Oh well.

Suddenly, there was a sharp pain in the Doctor's chest. His breathing slowed and his vision started to blur in and out of focus. He felt Rose's heart beating faster as he clutched at his chest. That's when reality hit him.

One heart! She's only got one heart! I can't survive in this body. I need to find Rose and-

"Ahhhhhh!" The Doctor screamed out in pain. He had to get out of this hospital, so he stood up, noticing that Rose's body was still in her original clothes.

Well, that's a good sign. I couldn't have been here that long, the Doctor thought to himself.

Jackie and Pete were forced to leave the hospital due to Jackie's aggressive behaviour towards the staff, which meant that the Doctor could sneak out of his room with ease.

He hailed a taxi and directed the driver to the Tyler Mansion. Once there, he rushed out of the car and around into the back garden where his faithful TARDIS was parked. A huge grin spread across his face as he ran inside.

"Now, time to find Rose. If she's in my body, she will be at Torchwood, Cardiff," he thought out loud, "Because Torchwood, London is too busy to deal with it," he repeated the words in a mock voice from when he had been shot.

He had got caught up in a war with Rose on the planet Clom, but he had got stuck in the cross fire. They had to leave the planet because two days into the war, a meteor would crash into the planet, wiping out the whole species. Of course, they also had to leave because of the amount of blood the Doctor was losing. He had assured Rose that it hadn't hit him in a fatal spot. If it was 2cm higher or 1cm lower he would be in trouble. When they had reached the TARDIS, he remembered that she was running low on power and had to go into lockdown, the only room left available was the control room. They went to Torchwood, but they had said that they were too busy to deal with such a small incident. He had barely managed to keep Rose from slapping the man hard in the face. They were told to go to Torchwood, Cardiff, who actually helped them. Although, he thought that was more to do with the fact that they were best friends with the crew, rather than anything else.

The TARDIS materialized in front of the door leading to the tourist information desk that disguised the entrance to the Torchwood Hub.

As he entered the small room, a sharp pain hit his chest again but he continued walking.

"Jack?" he called but there was no answer. "Gwen? Ianto? Anybody?"

A part of the stone wall, behind the desk began to move, revealing a passage way. The Doctor stepped behind the desk and into the dark tunnel. He was greeted by Jack, grinning at him widely.

"Hey Rose! Heard you and the Doc had a nasty fall. Are you alright?" Jack asked cheerfully.

"Yeah, I'm fine. Where's Ro- the Doctor?" He asked, hoping that Jack wouldn't notice the little slip. If Jack found out what was going on, the Doctor would be mocked for the rest of his life.

"He's in the medical bay."

"Thanks," The Doctor gave him a small smile but before he could move an inch, he collapsed onto his knees, screaming in pain.

"Rose!" Jack called the rest of his team back to the hub as he knelt beside the Doctor.

"Jack, I need you to wake the Doctor. Tell him that-" But before the Doctor could finish, Owen and Rose had rushed into the room. They ran towards him and when they reached him, Rose knelt down and wrapped her arms around him.

"Doctor, what's wrong?" Rose asked, panic rising in her voice.

Jack threw a confused glance at Owen who whispered an explanation about the strange body swap in his ear.

"Because this body has only got one heart, it can't hold a Time Lord brain!" The Doctor screamed once more in pain before the darkness consumed him.

A/N: Mwahahahaha! What shall happen to the poor Doctor? I know it's not been very funny so far but I PROMISE it will start to get funny in the next chapter!

I'll do a swap. I'll give you a virtual cookie and you review! Simples!