Notes: From a prompt that kalkopyryt submitted to the holidaysat221b community: I have read this in one or two fics, but not really developed as a main theme of the story … so: What if Rosie wants to pair John and Molly? How will Sherlock react and … how will he convince Rosie that Molly is for him and not for John. I'm imagining some angst in the middle because the silly man thinks this is a wonderful idea: Rosie gets a mummy and Molly gets a family. In fact, Sherlock sets up a date between Molly and John while he's babysitting Rosie

Wednesdays at 221B

Rosie frowned intently at the small square of card before her, tongue stuck out as she concentrated.

"I have blue eyes so I'm little b- little b. Daddy also has blue eyes so he's little b- little b. But Mummy had brown eyes. So since the bwue awwewe is recessive-"

"What do we say about gliding our 'l's,' Watson?"

She heaved a melodramatic sigh and rolled her (indeed very blue) eyes at him. Her teenaged years were going to be an absolute treat.

"Only when I'm trying to con a sucker by being cute."

"And am I a sucker?"

Rosie considered.

"Not always."

Sherlock raised an eyebrow, but had to say, "Granted."

"The blue allele is recessive… so Mummy must have been a big-B-little-b!"

She smiled a wide white smile up at her (admittedly doting) godfather, who filled out the Punnet square accordingly. Watson was quite precocious (though how could she not be, Sherlock thought, with two very intelligent parents and two extraordinarily intelligent godparents) but the manual dexterity necessary for writing was taking a bit longer to come along.

"Very good work, Watson. That's correct. Your mother must have carried a copy of the blue-eyed gene in order for it to appear in you, but because she also carried the dominant brown-eyed gene, it did not manifest in her."

"Did you check?" Rosie asked suspiciously.

"Oh, excellent work, Watson!" Sherlock clapped his hands, "Reflexive questioning of the argument from authority, there shall be buns for tea! No, I haven't. Genetic testing is still quite expensive. And in actual fact inheritance is rather more complicated than Mendel thought or than the Punnett square can capture."

Rosie switched instantly from the delighted "Mary" expression to the thunderous "John" one, glared up at him, and wailed, "Then why did I have to do this?"

Or maybe not John. That face contained elements of the full Mycroft. But he had consumed the entirety of Rosie's fifteen minute attention span on a challenging and highly skilled lesson, and therefore she deserved an explanation followed by a dessert - aka the Big Brother Protocol.

"It was what we call a lie-to-children," Sherlock explained, "And what do we say about lying?"

"Only when it's really important," Rosie mumbled.

"Exactly. The explanation I gave you isn't fully true, but once you've built up enough knowledge of chemistry and biology you can build upon this lie to learn things that are actually true. Now let's have cake."

A slice of black forest cake and a half glass of milk (he'd learned the hard way not to pour her any more liquids than he was willing to clean up) handily defused the small Watson-shaped bomb that had been about to go off. Rosie ate the same way her father did: precisely, surgically, and with great attention to the order on her plate (though not to the order on her face… he'd have to make sure she was well washed before he returned her this evening).

The question of inheritance had been much on his mind, lately… had John purposefully taught her to eat this way? Or had Rosie absorbed it without his knowledge, simply through the osmotic pressure of sharing a house and a life with her father? Or was it something more fundamental, passed down in the genes, a snippet of DNA that she would have brought with her even if John had remained forever in the well at Musgrave?

Melancholy, Sherlock? How very like you of late.

Shut up, Mycroft.

"So my hair is blonde because of Mummy and Daddy's blonde hair," Rosie commented, snapping Sherlock out of his own solitary train of thought and into hers.

"Mmm… hair's one of those tricky things. Your father had dark hair when he was a young man, he's just gotten grey. And your mother colored her hair. Furthermore, even though your hair is blonde now it may well be that you too will get darker as you get older, that's quite common."

Just like me, Sherlock. Do you remember?

He did, abruptly. Eurus had been even fairer than Rosie, in his earliest memories. The near-white of her hair had just been starting to shade into darker hues when she was taken away.

"You can color your hair?"

"Yes."

"Can I?"

"Unfortunately I haven't got any on hand at the moment but I can pick some up for next week. What color would you like?"

"Purple!"

"Right-o."

Rosie dabbed the back of her fork into the cherry filling and asked, more hesitantly, "So if you don't always get your hair and your eyes from your mum and dad… then could Molly be my mummy?"

"Um…" Utterly flummoxed, Sherlock stared across the table at Rosie.

"Apart from the fact that your mother seems to have typed Ctrl-C Ctrl-V on herself to make you?"

No.

"I was present at your birth. It was horrifying. Molly was definitely not there, I'd have remembered."

And no.

"Well, the coloration doesn't specifically rule it out… but… Mary was your mummy, not Molly," he hesitated, "You know, from your video? And your pictures?"

"Oh," Rosie said in a small voice.

Tragedy lurks, sometimes, in the most unexpected places. He should have stuck with fruit flies or pea plants.

Rosie brightened up, then, and said, "But if she married Daddy, then she would be!"

"What," Sherlock replied.

Rosie took on a didactic tone, gesturing with her fork, "Sometimes when you get a stepmother she is very cruel and bakes you into a pie or leads you out into the woods to get eaten by wild beasts. But Molly is not cruel. And so she wouldn't."

"I'm sure your father wouldn't marry anyone who would bake you into a pie, Watson."

Not intentionally, anyway. Though once John does finally hop back into the dating saddle I'll have to keep a weather eye on him, just in case. The man's picker is profoundly broken.

Rosie seemed entirely untroubled at the prospect of being devoured by beasts and/or cannibalized, another example of how she was a profoundly odd small child.

"Well, Sherlock… you really never know," Rosie mused, "And it'd be nice for Aunt Molly, too. Daddy could… lift heavy things for her. He's very strong. And he could buy her diamonds."

Rosie was hesitant about this last, as not being able to recall seeing the inside of a marriage had made her base her conceptions entirely off television.

"I don't think that's all there is to being married," Sherlock reassured her.

"And really who else is going to marry Molly?"

The child blinked up at him with her wide blue eyes, and Sherlock found himself saying, "Is it time for a nap yes I do think so."

Rosie went down without a fuss. The new full-day education was taking it out of her… John reported that she had shifted her bedtime more than half an hour earlier on nights she didn't nap, though of course the latest research suggested that children her age ought not to be encouraged to have routine daytime rest-

And Sherlock wasn't actually thinking about his weekly guardianship.

He was thinking about what Rosie had said.

After the debacle that was the Smith case, Sherlock had gradually come to accept that Mary's death had not been his fault. But there was a difference between fault and responsibility, and the responsibility lay entirely on his shoulders. Decisions Sherlock had made had led to the objective fact of a motherless child sleeping peacefully in her father's old room.

And Molly… oh, there lay fault.

He hadn't thought of her at all at first, except as a useful accomplice in Barts morgue and laboratories. But then even Sherlock had caught on to her social cues… the blushes, the way she touched her neck when she saw him-

Oh, he'd thought at the time, that's what she meant by coffee.

Then he'd used it, as he often used other people's weaknesses against them.

But Molly had proven herself more than useful, but crafty. Gradually she'd insinuated her tendrils through his brain and life and heart until she was far more his weakness than the other way round… until Sherrinford, when he'd finally admitted something that had been a matter of objective fact in his mind for years.

And like many other settled facts, would have better been left permanently locked up in there.

There was no possible way in which "The Story of Molly and Sherlock" reached any sort of romantically happy terminus. He was a Holmes, and always would be. The coldness of his brother and the madness of his sister were eternally present parts of his psyche.

Sherlock knew himself fully possessed of the capability to destroy the peace and happiness of a gracious, beautiful, infinitely kind woman. What else could he do but let her go?

Except she hadn't. Gone, that is. She'd accepted his love and returned it and simply adapted to the objective fact of life-as-it-is. Molly was still eternally present in his life, mostly smiling, partially happy… and solitary. In a way that she really ought not to be.

Was he capable of leaving his own selfish desires behind and changing that?

Rosie woke an hour or so later and came down the seventeen steps, her binky trailing behind her. In the living room she find Sherlock folded up in his chair, his hands tented below his chin.

"Rosie, I believe that we can make a match between your father and your Aunt Molly."

"What, seriously?" Rosie asked. She was sleepy, and so the question sounded rather sarcastic rather than the delighted wonder that he'd been expecting.

"Yes, I think so. We'd simply have to arrange for favorable circumstances."

Rosie looked up at him dubiously.

"Like… a date? With flowers and music?"

"Exactly like that."

Scenes from a date: Half of a conversation held on a public landmark

Sherlock, it's me. Yeah, look, we're on the Eye like you said but I'm not seeing the suspect at all and I'm starting to get worried we've accidentally stolen the capsule that some poor bugger was planning to propose marriage on.

No, I mean, there's an actual string quartet. Playing… I dunno. That song from "Scent of a Woman?"

Oh, Molly says it's called Por Una Cabesa. Apparently it's her favor-

No, fuck off with that, I said I don't want any champagne.

Anyway. There's a bloody persistent waiter in a tuxedo and roses and I don't know what all. Are… are you sniffling?

Oh, we're seeing a lot of that down at the clinic. Global warming spiking the pollen content. There should be some claritin in your medicine cabinet.

No, next to the arsenic.

Bloody hell. The thing's coming to a stop! I've got no idea how long we're going to be up here. Are you okay watching Rosie for a bit longer?

Yeah, I can hear her laughing. Right, thanks for that, see you later.

Wednesdays at 221B

"So, sadly, Watson, it didn't work," Sherlock concluded, "Nearly two hours in extraordinarily romantic circumstances and they simply said their goodbyes and moved on."

Very sad indeed, as he wasn't a selfish monster and only wanted the best for the people he cared about. Tragic. Really.

Rosie considered, deeply. Then she asked, "Does everybody like to do the same sorts of things when they go on a date?"

Sherlock considered, deeply.

"There you have me. I've no idea."

Rosie sucked on her front teeth in another Mini-Mary expression, and said, "Well, then, what would you do? If you wanted to take Aunt Mowwy on a date? What do you think would make her happy?"

He was probably imagining the faint hint of "You moron" at the end of her final sentence.

Scenes from a date: Slightly more than half of a conversation held at a controversial anatomical art installation

"Oh, wow, that's amazing. Look at the details of the musculature that they were able to preserve."

"Yeah."

.

.

.

"I mean obviously it's not perfect. The positioning of the organs isn't quite how it should be for someone actually standing on her hands. Typical physician's mistake… we really only see them lying down on their backs, after all. And the coloration is all wrong. Just look at that liver. They're never that pale."

"Yep, look at that."

"It must be an artifact of the plastination process. I never studied embalming, myself, people always confuse me with a mortician but it's really not part of the curriculum, though one of my professors was quite keen. It's important as a teaching tool if nothing else."

"Huh."

.

.

.

"Ooh, there's a little shop at the end."

.

.

.

"Of course there's some ethical concerns with this. They have tons of volunteers for the process but the actual work is done out of Dalian. China's kind of the Wild West in terms of organ and tissue donation. There's been allegations that executed dissidents have been used for some of the exhibits."

"Christ, really?"

.

.

.

"My God, that's…exquisite. How did they do that? Even the capillaries are perfectly preserved. They're almost like feathers, aren't they, when they're out on their own?"

"Molly, I'm just going to step out for a sec."

Molly had been too engaged in the exhibit to notice that John had been unusually monosyllabic. She turned away from the plastinated freestanding circulatory system to see his retreating back as he pushed through the crowds.

"John?"

"Text me when you're done!" John called over his shoulder.

Molly glanced over at the display John had been viewing… the cadaver of a woman, reclining on her side. This one had been dissected to open the uterus and show the curled eight month fetus that she had been pregnant with when she died.

It was remarkable, this intersection between science and art. But looking at it without her pathologist's eyes… it was also a tragedy.

She skipped the rest of the show and followed John out of the gallery.

He was sitting on a bench, looking out over the tourist boats cruising down the Thames. Molly sat next to him and folded her hands in her lap. John's lips were tightly folded, his own hands in fists.

They sat in silence for a few minutes until John said, "I never had problems in the cad lab in medical school."

"Mmm," Molly said, "Because every year I get a new crop of students in and every year I can guarantee at least two fainters. Always men."

She smiled.

"I'm very nice about it, but secretly I think they're pussies. At least you didn't hit the floor. Though I'm going to ask Mike Stamford about your med school days."

Molly reached over and took John's hand in hers, twined their fingers together, and after a brief hesitation he let her.

"Seriously, though, sometimes… it's hard to mentally... detach the body from the person who was in it. Loads of people can't do it at all, and almost everybody finds it hard at least some of the time. Even me."

Like the tall man, whose name nobody had ever been able to determine, who looked more like Sherlock than his actual brother did. The woman without her face. A few others, here and there, over the years.

John interrupted her musings, saying, "And I see murder victims all the time, obviously. But when we do that I'm mostly focused on the crime, not the person."

He chuckled ruefully.

"I should have just given the other ticket to Sherlock and let him go with you. I bet he'd have got a real kick out of it."

"He really would, to the point where I'm sure he's already been. But why'd you buy the tickets, then, if you didn't want to go see it?"

"I didn't buy them," John replied, "I won them off the radio by knowing which was the only blond Traveling Wilbury."

He sounded quite proud of this accomplishment, and Molly smiled, asking, "Okay, I give, which?"

"Tom Petty."

"Nice."

A breeze blew along the river, lifting their hair. John put his other hand on hers and gave it a squeeze before letting go.

"Fancy some lunch?" he asked, "No corpses, I'm afraid."

"I think I can manage without for a bit," Molly smiled.

Neither of them noticed the black-clad figure on the other side of the river, observing them through binoculars.