"Deduce This"

Strolling around Greenwich while it was being repaired was possibly not the greatest idea, especially when SHIELD agents hit the scene. Darcy associated Agent iPod Thief with them, which was probably why she hallucinated him. Shaking her head, she wandered away, wanting to avoid the jackbooted thugs for as long as possible. Diplomatic immunity with Thor only extended so far, after all. So she decided to go through the underground tunnel, the one running beneath the Thames. She hadn't been there before, and wanted to see whether it really was as eerie as everyone said.

There was a tall, curly-haired man staring at the scene of destruction and muttering to himself. He clearly wasn't SHIELD – the long coat, the scarf, and the insane look kinda gave it away – so Darcy risked strolling over to him.

"Got a problem with it, mister?" she asked.

"There is something I cannot work out about this," he said. Her mouth fell open, and she saw the moment it clicked for him when his eyes widened. He looked down at her, and she raised her eyebrows as he scanned her body.

"You haven't got any experience with aliens, have you?" she asked.

"Aliens?"

"The kind that fall from the sky. Or come via a rainbow bridge run by a guy named Heimdall. You heard of Thor?"

"Ah, yes," he said, nodding. "Because we're all meant to believe that a mythical Norse god is running around the streets of London."

"He doesn't need to run. He has a hammer he uses to fly around. The cape just makes it look more dramatic. I don't think he's seen The Incredibles."

"Mjolnir? You believe in such things?"

"I've seen Mew-Mew myself! My boss, Jane, she's Thor's girlfriend. She's been to Asgard and everything. And you'd believe in gods, too, if you'd seen Thor's arms up close."

"I believe in science," he said. "Not mythology."

"Hey, I'm into science, too," she said, giving him a gentle punch on the shoulder. He frowned. "Okay, poli-sci, but—"

"But you work as an intern in a field of science with which you are unfamiliar. You are obviously from North America, not from the deep south, nor Canada, judging by your accent. You deferred your studies to work with your boss in London, and clearly you have seen activity of this nature before, not to mention your run-ins with the American government—"

"Hold up, hold up," she said, raising her hands to stop him. "How did you know all that? What're you, a mind-reader?"

"I deduced you," he said. "If the rumours are to be believed, this boss of yours is the astrophysicist Jane Foster. I have no interest in the solar system; it has nothing to do with my line of work." He cocked his head. "I am interested in how you came to be my soulmate."

"I was born with my soulmark. What's your story?"

He hesitated, and then held out a hand. She shook it. "Sherlock Holmes, consulting detective. And you are…?"

"What, you couldn't deduce that?" she asked.

"Not without pocketing your wallet and consulting your ID. You're hardly the type to wear name labels in your clothing. Not since you left high school. I find it interesting that you refer to your primary level of education as elementary, though, a favourite word of mine. Do you know why that is?"

"No, I don't," she said, a little dazed. "Darcy Lewis. Intern to Jane Foster, friend to a Norse god or alien, it's open to interpretation."

"What do you believe?"

"I'm on the fence about that. Until I see Asgard, I'm not committing myself one way or another. But the dark elves were definitely aliens. From another planet equals aliens."

"Mmm-hmm." He looked her over again, this time not so much assessing, more looking at her for the sake of looking. He was welcome to.

"What does a consulting detective do? Just to warn you, if you say that it's a detective who consults, I might punch you on the arm again, and this time I won't hold back."

He half-smiled. Or smirked. It was hard to tell, since he'd been pretty expressionless up `til then.

"When Scotland Yard needs my help, I assist them in their investigations," he said. "I also work on a private basis."

"Get a lot of work?"

"Considering the rising rate of crime in London, yes, I do. Especially as the majority of the detectives at Scotland Yard are incompetent at best."

"Wow. Really not feeling safe here any more."

"Are you any safer in America?"

"Well, I'm less likely to get shot at the supermarket here. But I'm not safer from aliens, as it turns out. C'mon." She turned away from the scene. "I was gonna walk under the river. Wanna come with?"

"Very well," he said. "How long are you in London for?"

"Until Jane wants us to leave."

"When will that be?"

"I don't know."

"If you would prefer to listen to your iPod, I won't be offended."

"My iPod?"

"The musical device you keep fiddling with in your coat pocket."

"Ah. Yeah, I love my iPod. I'm glad I didn't lose it in the alien invasion."

"Tell me about SHIELD," Sherlock said. And really, what kind of a name was that? Then again, he'd probably ask her what kind of name Darcy was.

"You wouldn't rather talk about me?" she said. "Or you? Or us?"

"I can discover anything I wish to learn about you either in person or online. No doubt my brother has already discovered everything he can about you, and will meet us in a large black car at the other end of the tunnel."

"…What?"

"Mycroft works for the British government. Or, should I say, he is the British government. He will wish to meet my soulmate."

"Will he scare me?"

"He scares everyone. You?" He examined her again. "I doubt it. You may surprise him."

"Not if he's pulled up my history using one of his lackeys. But how would he know?"

"There are cameras everywhere. People who lip-read. Facial recognition. He will undoubtedly have your full dossier by the time you meet him."

"Yeah, that's not scary at all. He should work for SHIELD."

"I think he prefers working for the queen."

"Queen and country, huh?"

"No. He answers directly to her, on occasion."

Darcy nearly tripped on a non-existent stone, and Sherlock caught her around the waist to stop her from falling. She clutched his arms, and then ran her hands up to his shoulders.

"Well, aren't things looking up?" she said.

"…Yes. We had best get moving."

"Okay, Sherlock," she said, entwining her gloved hand with his. "So, tell me all about yourself. What've you been doing the last five years of your life?"

"Chasing down a criminal mastermind, faking my death for two years, nearly getting sent on a suicide mission after killing a blackmailer, and currently working to find out who is behind the criminal mastermind's return, considering that he committed suicide in front of me. Oh, and I was the best man at my best friend's wedding, which was before his new, pregnant wife turned out to be someone quite different and shot me."

"…Sounds fun."

"And you?"

"Well, I studied for awhile, took on an internship for extra credit, helped stop an alien robot from destroying New Mexico. Uh, hid out in Europe with Jane when Thor returned to stop his crazy brother from leading an alien invasion in New York City, then came over here where we stopped the dark elves from destroying all nine realms."

"I suppose this makes us somewhat compatible, then."

Darcy laughed kind of hysterically. "Yeah, I guess you could say that."

"I am still baffled as to why Fate chose you for me, but," there was that smirk again, "I look forward to finding out why."

"You don't think your brother will have the answers for you by the time we get out the other side of the tunnel?"

"He is cleverer than I am, but I am still a genius in my own right."

"And I'm used to working with those. I'm kind of a scientist wrangler. I keep them alive by feeding and watering them and making them sleep sometimes."

"John would say that you are the perfect woman for me," Sherlock said, moving her hand so that it was tucked in the crook of his elbow. Darcy leaned into his side as they continued to walk through the ghostly greenish tunnel under the river.

"He's your best friend?"

"Yes. My… only friend, really."

"You've got me now. My friends are gonna see you as their friend, too."

"I may alienate them. Very few people can stand to be around me for a great deal of time."

"Aw." She stopped and kissed him on the cheek, then tugged him along. "We're nearly there. Is there anything else I should know about your brother?"

"You will learn enough simply through conversation with him. He will take us straight to Baker Street. Unless you have somewhere else to be?"

"That's a tube station, right?"

"Yes."

"Great. I have one of those app things which'll help me get back to the apartment where we're all staying at the moment."

"Darcy… if you had no real reason to return to America, would you consider staying here in London? With me? Only if I do not drive you off."

She poked him. "What'd I say? Less likely to be shot in the supermarket here. And it's not like another alien thingy is gonna happen anytime soon. The convergence is kind of a one-in-a-millennium event."

"Mycroft will be delighted to hear that."

"Will Mycroft be 'delighted' to meet me?"

"He will be relieved that I have found my soulmate. He has yet to find his."

"Wait, really?"

"He would not tell me if he had, I'll admit that," Sherlock said, leading her up to the daylight, and the promised black car. A man with an umbrella was leaning against the door, and he looked up as they approached.

"This your brother?" Darcy said. "I can kinda see the resemblance."

"No need to start our relationship by insulting me," Sherlock muttered. Darcy poked him again, earning herself an unamused eyebrow-raise.

"Miss Lewis," Mycroft said.

"You can call me Darcy," she said, shaking his hand. "Nice to meet you, Mycroft."

"The pleasure is mine," he said. "Please climb into the car. Would you like to be taken to the flat you share with Dr. Foster, Dr. Selvig, and Mr. Boothby?"

"And Mr. Odinsson," Darcy said. "The god formerly known as Prince Thor. But he's not on the list of renters, and seriously, you know about Ian?"

"I know about everything, right down to what you had for breakfast."

"And brand of toothpaste," Sherlock added.

"You hadn't already told her your deductions?"

"I was attempting to make a good first impression, Mycroft."

"I'll be okay with Baker Street," Darcy said, trying to stop the brotherly argument.

"You may wish to find a better place – or at least learn to tidy up after Sherlock – once you are married," Mycroft said. Darcy nearly hit her head on the way into the car, and Sherlock grumbled something as he followed her.

"Married?" she said. "Dude, we just met twenty minutes ago."

"Our parents will be eager for grandchildren," Mycroft said. "They have certainly dropped enough hints."

"They're unlikely to get any out of Mycroft," Sherlock said acerbically. Darcy just buckled herself in with half-numb hands.

What the hell had she gotten herself into?

After bringing Mycroft and Anthea into the Jane/Jemma chapter, there was a call for more Sherlock crossing over. Lavanyalabelle and Bullla both requested Darcy/Sherlock, which could kind of work. I'm still writing Deadpool/Jemma (with background Audrey/Phil), and the chapter's already exceeding 8000 words, bordering on 9000. No idea when I'll have it finished, so I thought I should speed-write a lighter one before the potential heap of angst.

Please review!