Disclaimer: This fanfiction is not written for profit and no infringement of copyright is intended. Not beta read so all mistakes are mine.

MONSTERS!

"Daddy! Daddy!"

Rosie Watson comes thundering into Mrs. Hudson's flat, her thin blond plaits fluttering behind her, her little Doc Marten boots pounding on the floorboards. Her favourite stuffed toy, Penny the Penicillin, is clutched to her chest and her eyes are wide as saucers; previous experience has taught John that his daughter has either discovered something terrifying or wonderful, and the likelihood of either is entirely dependant on whether she was with Uncle Sherlock when the breakthrough occurred.

With an indulgent smile Mrs. Hudson pats her on her head as she dodges around the older woman's legs to fling herself on her father, Penny the Penicillin smacking him soundly in the backside as she does so.

The "oomph!" noise he makes causes Martha to chuckle.

"Alright then, young lady," John says, staring down at his daughter with what he hopes is a mixture of sternness and reassurance. "What's brought all this on, eh?"

Rosie stares up at him, lip wobbling, and it's only now she's close that John sees her eyes are glassy with unshed tears. Immediately his face softens.

"What is it, sweetheart?" he asks more gently, settling himself on Mrs. Hudson's couch and swinging the child up into his lap. He sets her on his knee. "What's the matter?"

The little girl stares up at him and sighs, giving every impression of a Christian who's about to be tossed to some particularly peckish lions.

"It's- It's about Uncle Sherlock," she says, dropping her voice until John has to lean in to hear her. "I saw him upstairs with Aunty Molly and, and I think... I think something's wrong with him!"

And with this she promptly bursts into tears, letting forth a stream of babbled explanations about how she'd snuck into the living room in 221B in order to surprise her Uncle. About how she's been so proud of herself for managing to sneak up on the legendary Sherlock Holmes. She'd hidden behind John's favourite chair, about to jump out and surprise her Godfather, when-

"When Aunty Molly came in," she says. "Uncle Sherlock was pulling her into the flat and he had his mouth on her face and she- Daddy, she couldn't have been able to breathe! She was making these moany-type noises, as if she was suffocating!"

In horror Rosie explains that her beloved Uncle then picked up Aunty Molly- "And her arms were all over the place, I think she was trying to fight him off-" but before he could succeed in eating her face Sherlock managed to get her into his bedroom and slam the door.

A couple of moments later Rosie started hearing moans and screams and banging-type things, as if Uncle Sherlock and Aunty Molly were fighting on the bed.

"So I came down here to tell you, Daddy," she says, voice creaking, "because I think something's wrong with Uncle Sherlock, and you always tell me if something's wrong I should come and tell a grownup-"

John stares down at his daughter, so like her mother, and sighs. Squeezes the bridge of his nose.

He is going to kill Sherlock and Molly over this.

"First of all," he says, forcing his voice bright, "Well done on coming to tell me: You were right to ask." Over Rosie' shoulder he sees Mrs. Hudson smile. "Secondly, Uncle Sherlock was not trying to eat Aunty Molly's face." Rosie opens her mouth to disagree with him but he shoots her a quelling look and she promptly closes it again. "I know that's what it may have looked like, Rosie, but that's not what he was trying to do."

And he smiles reassuringly, hoping somewhat forlornly that that will be the end of the matter. But of course it won't- Not with his girl. For Rosie crosses her pudgy little arms over her chest and pouts. Cocks the eyebrow that makes her look heartbreakingly like her mother.

"So what was he trying to do?" she asks pointedly, in that tone that, just for a moment, makes John wish he had a rather less intelligent child.

It takes him a moment to summon an answer.

"Uncle Sherlock and Aunt Molly were doing something grownups do when they like each other," he says eventually. "They- You know how Aunt Anthea and Aunt Sally sometimes hold hands in public and dance?" She nods suspiciously. "Well, it's like that but more... More grownup. And more private.

People usually only do it with people they really care about."

Rosie's eyes light up. "So Uncle Sherlock was telling Aunty Molly that he likes her?" She asks. "The way Uncle Mycroft likes Aunt Alicia?" John nods, relieved at not having to be more specific.

Maybe there are good points in having such a clever child after all.

"Yeah, love," he says. "Exactly like that. And considering how long it's taken Uncle Sherlock to get his thumb out and tell Molly how he feels, maybe we can just keep what you saw between me and you for the time being, eh? So he doesn't get embarrassed and chicken out."

Rosie frowns. "Is this going to be one of those things he's silly about, like my trying to finish his experiments?"

John's look is stern. "He wasn't being silly about that, Rosie," he says. "You know you're not allowed touch anything marked as body parts in the shared fridge." The pouting lip makes a mutinous reappearance and he rushes on. "But yeah, it's like that. Uncle Sherlock will tell everyone when he's good and ready, and you will let him, is that clear, Rosie?"

The little girl looks at him quizzically for a moment and then nods. "Penny and me'll keep it to ourselves for the time being- Won't we, Penny?"

And she smiles at the plush toy, holding it up for John to kiss before scrambling down off his lap and skipping over to Mrs. Hudson, who just happens to be making fairy cakes at the moment.

Fancy that, John thinks dryly. She really does get her timing from her Mum...

As always when he thinks about Mary, he feels a pang. Given how much like her Rosie is he' s come to accept it will always be so. But rather than dwell on that he takes out his phone and pulls up his best friend's number. Thinks for a moment and then smiles as he sends a text-

Upstairs, in Sherlock's bedroom, his phone pings and he picks it up. Looks at it. It could be a case, after all.

What he sees makes him laugh, though.

"What is it?" Molly asks, her voice husky, her hair bed-tossed and ravishing. She's leaning on Sherlock's chest, her weight on him, and oh but he likes the feel of that.

"I have, apparently, scared the living daylights out of Rosie and destroyed her innocence," he announces. "John says I shall have to buy her a pony in recompense."

Molly's cheek pink but before she can become embarrassed Sherlock pulls her to him. Kisses her soundly.

He is smugly pleased that when he pulls away she is thoroughly breathless.

"Even if I have to buy her a whole stud-farm," he says, "it's still bloody well worth it..."

And with that he and Molly go back to their mission to steal one another's breath for the day...