The Doctor turned on his heel to find Sherlock Holmes, tall, pale, thing in a belstaff coat following him into the TARDIS.

Again.

"Look, I'm glad you and John helped," the Doctor said as he opened the door.

"You would have died if we hadn't," said Sherlock.

"No I wouldn't," said the Doctor.

"Yes you would," said Sherlock. "When aliens with razor lined tentacles are filleting vagrants in the London sewer. You didn't stand a chance, no matter what you are."

The Doctor sighed. "You had no idea what it was despite your deductiv-ity oh so cleverness. If I hadn't told you."

"You call bursting in the morgue like your on amphetamines, while looking like thirties era Oxford don, help?" Sherlock sneered.

"I helped! And that Molly Hooper is cute! You know I need a new companion..." Doctor began.

"...She's mine," Sherlock growled.

"So not single anymore?" The Doctor gave a smile.

"No! She's my friend, you don't take my friends, I don't take yours," Sherlock. "That was our deal after the first time."

"Yes and aren't you glad, that you listened to me? I mean having your best mate nearly killed by giant woodlice because you thought-"

"Yes. Yes. Now in your box. We need to come up with a plausible story for all this. One Scotland yard and the media will buy." said Sherlock.

"We? I always come up great ones!" Said the Doctor.

"No, you don't. The Sun may have swallowed them. But Lestrade didn't, no matter how sarcastic I was." Shelock sighed.

"Fine. Don't touch anything, not like last time." The Doctor said as he opened the door.

"When did I ever-"

"Only the last four times..." The Doctor said. "And we are not solving Jack the Ripper or The Roanoke colony. I know what happened and you don't need to know."

"How about a public hanging? Or the black death? We could go to Tyburn and be back before-"

"Hello!"

A pale dark haired young lady in a long clingy, spangly, gold dress popped out from under the console.

"River Tam! How many times do I have to tell NOT to stowaway!" The Doctor yelled. "Right, Sherlock, go home. I have to get Ms. Tam back to her own time."

It was to late. Something had changed in the air. Sherlock and River were circling nearer. She was blinking up at him as if she'd never seen such a person. And Sherlock for his part was doing a million observations and deduction about her. They both smiled of a second fraction about a part. There could be romantic music in the air. The Doctor realized he might as well be furniture... in his own TARDIS.

"How did you manage to stowaway?" Sherlock asked. "I've attempted it, he always finds me and kicks me off."

"The TARDIS has five ways of sensing stowaways." River said.

"Five?" asked Sherlock. "I only noticed and disabled three."

"I got all five this time. The last is very strange a slight change in the TARDIS's hum, I changed the resonance to something that a Time lord wouldn't pick up on." River said she was circling closer. "I like your coat."

"Of course, brilliant! Oh thanks, it is a nice coat. It was the last one, they stopped making them. My brother bought for me. Makes up for him being such a git," said Sherlock.

"Speaking of brothers," The Doctor. "River, Simon will be worried sick. And Mal. And everyone else. We've got to get you back to you know your own time."

"I'm an adult now," said River. "And they don't let have fun, they are always worried... I'll do something..."

"Yes. Just because a person happens to be a different and their mind doesn't work like a dumb normal one, they think your sick and dangerous." Said Sherlock.

"Sherlock? You know, River is from far, far in your future. In fact earth doesn't exist anymore." said The Doctor. "And River this is 21st London. I just think you should know."

"So? You always said that sort of thing doesn't matter," Sherlock said.

"I've always wanted to see Earth that was," said River.

She was touching his coat, rubbing it... he was letting her. The Doctor could see he glimpsing at her with those pale eyes, like a cat who lived in a world of dogs and had finally met another feline. Oh no...

"Can I give you a tour, of London at least?" asked Sherlock.

"Why not?" said River.

"No, No, no..." The Doctor said. "I'll come with you. I know all about London, tons of stuff!"

"I think I'd rather just go with Sherlock," said River.

"Since you didn't want either of us on your TARDIS you should be happy," Sherlock said.

River reached out her hand to Sherlock, he looked down seemed to hesitate and then took it, happily.

"Can we eat?" asked River as they walked off.

"Dim sum?" Sherlock suggested.

"What's that?" asked River.

The door closed behind them.

The Doctor put his hands in his face. Then reached for the phone. He dialed:

"Hello, Rory! Can I have the number of your cousin John Watson? Yes it's about his crazy detective friend... long story.. hope it won't end the world..."