Jack stared at the narrow-eyed version of himself, and the other Jack stared back. A look of both horror and surprise was visible on both faces. The Doctor groaned and slammed the Tardis doors shut before running to the centre and hastily pressed some buttons to get them away.

"What the hell's going on?" cried Martha as the Tardis hurtled them away. She noticed Jack was looking slightly green. "Jack, are you OK?"

"Of course he's not OK!" yelled the Doctor "How would you feel if you had seen yourself like that?"

Martha thought. Then shuddered.

"Anyway" the Doctor continued to Jack. "That was a big mistake, me pointing him out. I don't think you two were ever supposed to cross paths. I just hope that-"

The Doctor was cut off by a massive jolt from the Tardis.

"Ah. I think we've just created a hole in this universe"

Jack stared at him. "And that's not good, right?"

The Doctor shook his head weakly as the Tardis rocked violently from side to side. Martha was shocked to see that his eyes were wide with horror. This scared her and Jack more than anything.

"Brace yourselves!" cried the Doctor urgently as the Tardis landed with a force that flung all three of them to the floor.

Jack looked up, shaking slightly. He pulled himself to his feet and helped Martha up too. They stared at the Doctor, who was sitting against the centre of the Tardis. For once, he was speechless.

"Doctor?"

The Doctor turned to Jack

"We fell out of the vortex, right?" A nod from the Doctor encouraged him to continue. "Does that mean we could be in a parallel universe?" Another nod. "Then…could this be…"

"Rose's universe?" finished Martha.

The Doctor looked hard at Jack. He sighed.

"Unlikely. It's literally a billion to one chance. And it's another billion to one chance that if we are in the right universe, we're on Earth. Still, worth a look."

Jack joined him at the doors of the Tardis. They were pulled open to reveal a blue sky, tall buildings and humans. Normal humans. They were, indeed, on a parallel Earth. Martha pulled a newspaper down from a kiosk.

"Well, would you look at that? London, definitely, and the year 2010. Not far off the original."

There was a sound of footsteps behind them as they stepped out further onto the pavement. A baby started to cry as a woman's voice became audible.

"Oh, my God!"

The Doctor spun on his feet. Jackie Tyler, closely followed by Pete Tyler, who was carrying a beautiful three-year-old girl, was running towards him, her shopping discarded on the pavement. Her arms were outstretched and she pulled the Doctor into a bone breaking hug as soon as she was within reach.

"Jackie?!" gasped the Doctor. Then "Ow!" as she slapped him around the face.

"You broke my baby's heart!" cried Jackie, continuing to hit him with every word. "She was crying for months once you said goodbye!"

Jack leant forward.

"Seems like we made that one in a billion chance" he whispered into the Doctor's ear. The Doctor couldn't say anything. Had they really ended up back in that parallel world? Emotions overwhelmed him and he found himself running back into the Tardis, just to pull himself together. He found himself both laughing and crying as he started to dance around in the blue box. Jack poked his head around the door and laughed to see how happy he was. Suddenly, he stopped and frowned.

"How did that hole appear again? In the exact same place?"

Jack shrugged.

"Maybe you only patched it up instead of sewing it completely back together?"

The Doctor contemplated this thought, and then grinned again.

"Rose"

Jack nodded and smiled as the Doctor bounded out of the Tardis.

"So! Can I see Rose? What about Mickey – how's he?" he asked as he swept Jackie up into another hug.

"Mickey's fine, he's still with us, living with his Nan, bless him. Rose…she's in hospital at the moment, Doctor. She was in a car accident two days ago. Still out cold."

The Doctor's eyes widened with worry.

"Can I see her?"

Jackie nodded and started to walk away, beckoning him to follow her. As the Doctor did so, Martha sniffed and reached in her bag for a tissue. Jack hugged her, holding her tightly while he tried to comfort her as she wiped her eyes. She didn't want the Doctor to see her cry. If he even noticed now.

"Rose?" the Doctor whispered as he approached her bedside. He reached out to hold her hand and softly stroked her palm with his thumb. As soon as he touched her, Rose's eyelids fluttered open. The Doctor grinned as Jackie gasped. He turned to her and waved his other hand.

"Healing hands" he smiled.

Rose was confused as she came round. There were six heads swimming into focus, not the usual four that stayed by her constantly. Jackie, Pete, Mickey and the baby – nobody else was supposed to be there. As the nearest face became clearer, Rose gasped. Surely it couldn't be…

"Doctor?" she whispered. "Doctor!"

She let him hug her tightly and clung to him like she wished she could have done that day they had to say goodbye for the last time. She laughed, completely forgetting the pain she was in, and found tears rolling fast and thick down her cheeks. The Doctor let her go and studied her face, tears also glistening in his eyes. He squeezed her hand as her eyes fell on Jack, causing her to emit another shriek. Jack hugged her and kissed her forehead as fresh tears started to flow. He tactfully failed to mention that it was her fault he couldn't die. Then Rose's eyes landed on Martha, who smiled.

"I'm Martha."

Rose turned to the Doctor, hurt and tearful.

"You replaced me?"

Feeling Jackie's glare bore into the back of his head, the Doctor began to protest.

"No, no, no! I could never replace you! I just…got lonely."

Martha fought back tears.

"He talks about you all the time, seriously. Never stops."

The Doctor nodded earnestly.

"I never got to say it before, so believe me, I'm going to say it now. I love you, Rose. Always will."

Martha couldn't take it. She crept from the hospital wing, and once in the corridor, broke into a run. She barged past nurses and doctors, and as she ran out of the door, she stopped dead. The narrow-eyed, fanged Jack Harkness was standing right in front of her, grinning maliciously.

Back up in the hospital wing, the Doctor failed to notice the terrified scream that was carried up on the wind from the front of the hospital.