The large bay window of the Watson's home let a shower of afternoon light into the living room. Bottles, blankets and soft toys littered every surface as Molly and Mrs Hudson stood taking photographs of the couple as they sat on the couch with their new-born daughter; the sweet new baby sleeping soundly in her mother's arms.

"What about a name?" asked Mrs Hudson.

"Catherine," John replied confidently.

"Uh, no we've gone off that," Mary added quickly.

"Have we?"

"Yeah."

Sherlock stood across the room, his eyes glued to his phone. "Well you know what I think…"

"It's not a girl's name!" the pair replied in unison.

A half smile crept across his mouth, creating a dimple in his cheek.

Across the coffee table, Margaux sat on the edge of an armchair. She was leaning forward with her elbows propped on her knees, her chin resting on her fists. Her bottom lip puckered as she cooed over the tiny infant.

Mary glanced across to her and giggled. "Do you want to hold her again?"

"Yes please." She stood up and hurried over, taking John's place on the couch as he walked over to Molly and Mrs Hudson.

Mary handed her the baby carefully. Margaux cuddled her to her chest, resting her cheek gently on top of her head.

"N'aw," she said, swaying gently. "You forget how small they are when they're fresh."

"Fresh?"

"Sorry. New."

Mary smirked. She loved the moment's when Margaux's 'weird' seeped through. "Is she making you broody?"

"Oh, god no," she leaned in, speaking quietly. "I actually thought I might have been… You know… And I almost had a breakdown."

"You thought you were pregnant?" Mary whispered back.

"Mhm. It was just a scare thankfully. I've never been so happy to see my period in my life."

The baby began to stir. Margaux stood up instinctively, patting her gently on the bum and soothing her with shushes. Mary sat back, perfectly happy to let her handle it.

Margaux walked slowly across the living room to Sherlock's side.

"Cheer up, Uncle Sherlock," she said, taking the baby's hand and patting him on the arm with it.

He looked down at them, his face smooth and unmoving, like marble.

"Oh, come on, crack a smile. Look how cute she is."

"All babies are 'cute'. Cuteness is an evolutionary trait in babies, designed to compel adults to want to take care of them so they don't die or get eaten."

She paused for a moment and blinked a few times. "Do you want to hold her?"

"Sorry. Can't. Busy."

John approached them with awkward steps, sighing nervously. "So, er, you two… We would like you to be godparents."

Margaux gasped, smiling broadly as she spoke. "Really? Us?"

"God is a ludicrous fiction dreamt up by inadequates who abnegate all responsibility to an invisible magic friend," said Sherlock, his eyes never leaving his phone.

"Yeah but there'll be cake…" said John. "Will you do it?"

"I'll get back to you."

John sighed.

"He'll do it," said Margaux, stopping John as he walked away. "We both will."

John smiled a silent thank you before making his way upstairs.

Sherlock raised an eyebrow. "You speak for me now, do you?"

"Yes. Yes I do," she replied plainly.

III

She was christened Rosamund Mary Watson a few weeks later. Sleeping beneath a bundle of white lace and silk as people fussed over her at the church. Rosie was the epitome of joy; a beacon of innocence amongst the sullied lives of those around her, like a ray of light at the end of the dark tunnel that had been the past year.

The same pub that had hosted her parents' engagement party was now strewn with balloons and flowers, bunting of blush pink and white, banners with 'Rosie' painted in smooth cursive. Children ran around the dance floor in their smart clothes, sliding on their knees and playing with confetti from the tables. John and Mary mingled with their guests, showing Rosie off and thanking people for their gifts. Sherlock sat at a large table with Margaux, Mrs Hudson, Greg Lestrade and Molly. Vaughan was playing with the other children as Sherlock watched him run around in his shirt, tie and tweed waistcoat. His dark, wavy hair was coiling wildly, fighting against his mother's attempts to style it. The conversation at the table blended with the music playing from the speakers. If he really cared to focus, he knew he could distinguish what they were saying. But he didn't care; he loathed idle chitchat – it was nothing more than a waste of time and brain capacity.

He snapped his head around to Margaux who was sat next to him. "John said there would be cake."

She looked him up and down, her eyes settling on his hands as they sat empty in his lap. "I don't believe it – all this time, the only thing we needed to get you off your phone was the promise of cake."

He looked down at her, straight-mouthed and unamused. She laughed and placed her hand comfortingly on his arm.

"I'm sure they'll be opening the buffet soon," she said.

Molly cleared her throat. "So, Sherlock…" she began timidly. "Greg was just telling us how just this week alone you've solved three cold cases."

"Yes… And?"

She rolled her eyes and took a sip of her drink. "Why do I bother?" she sighed quietly.

"Oh, the boys have been so busy," said Mrs Hudson. "It's lovely. Just like old times." She smiled.

Sherlock looked across the room to John as he stood holding his daughter, his glowing wife by his side. Mrs Hudson was right, it had been like old times, just for a while. But it wasn't. Everything was different now. Not just John, but himself too. He could feel the change infiltrating him like a virus; softening his grimaces and dulling the sharpness of his tongue.

III

They ate cake. Much to Sherlock's pleasure.

Music played as guests began to filter out, collecting their excited children and thanking John and Mary for the invitation.

Lestrade checked his watch. "Right, I'm gonna head off."

Sherlock peered up at him. "Gordon has a date…"

"Greg," Margaux corrected.

Lestrade rolled his eyes, ignoring his goads.

"Ooh, where are you going for your date?" asked Mrs Hudson.

"I… I never actually said I was going on a date."

"No, but Sherlock did so obviously you are."

Sherlock smirked.

"Alright fine, I met her at the pub last weekend. We're going–"

"Mini-golfing. How… sweet?" said Sherlock sarcastically.

"Will you stop that." Lestrade huffed.

Mary joined the table with Rosie in her arms, sitting down with a smile. "Stop what?"

"He's doing his deduction thing on me. Bloody annoying."

Mrs Hudson asked to hold the baby. Mary handed her over, watching as she and Molly cooed and fussed. She never thought this would be her life; that she would one day be someone's wife, someone's mother, that she would one day have a name that she was proud of.

"I'm going to call a private hire cab if anyone wants a lift home?" said Greg.

"Oh, yes please," said Molly. "We'll meet you outside in a few minutes."

Greg nodded, taking his phone from his pocket and heading for the exit.

Mary turned to Sherlock and Margaux, watching as Margaux finished off her drink.

"Sure you don't want to stay for a bit?" asked Mary. "I'll order us something stronger, celebrate the fact we can both drink." She laughed.

"Why wouldn't she be able to drink?" asked Sherlock.

"Well because of the whole pregnancy scare…"

He furrowed his brow, blinking quickly. Confusion did not come around often for Sherlock. But when it did, it was unsettling; twisting his face in a way that made him unrecognisable.

"I've put my foot in it, haven't I," said Mary.

Margaux let out a sigh.

III

Lestrade opened the door to the cab, gesturing for the women to climb in.

"Oh thank you, Greg," said Mrs Hudson. "You're such a gentleman – I've got absolutely no idea why Sherlock thinks you're annoying."

He pressed his mouth into a straight line, walking to the front passenger side of the car. "Nice. Well at least the feeling's mutual."

Molly climbed into the back, leaving the door open as she saw Margaux approaching with Vaughan.

"Come on, it'll be a squeeze but we'll manage," said Molly as she lifted Vaughan into the cab and placed him on Mrs Hudson's lap.

Margaux followed, lifting one leg over the threshold of the car before a large hand wrapped around her arm and pulled her back.

"Thanks, we're going to walk," said Sherlock before closing the door and waving to them through the window.

"Hey! Vaughan's in there," Margaux protested as he walked her away, still gripping her arm.

"He'll be fine, I'm sure they won't lose him."

She rolled her eyes, pulling herself free and straightening the sleeve of her dress.

"You're not seriously suggesting I walk all the way to Baker street in these shoes…"

"How else would you walk?"

She scowled at him. "They're killing me, Sherlock! I can barely stand in them without almost breaking my ankles."

He ignored her, flicking up the collar of his coat and walking down the street. She followed reluctantly, almost tripping as they crossed the road. Sherlock kept his eyes forward, his jaw clenched, hands in pockets. They walked quietly side by side, the only sound coming from the clacking of Margaux's heels against the uneven pavement.

"Well go on then," she finally said as they turned onto a quiet street. "I know you want to say something."

He closed his eyes for a moment before speaking. "Why didn't you tell me?"

"Tell you what?"

"Don't be obtuse, Margaux. Why didn't you tell me that you… thought you might be…"

"Because that's just it. I thought I might be. But I wasn't–" Her foot slipped from underneath her, causing her to fall forward.

Sherlock reached out and caught her by the arm, steadying her in place before continuing to walk. Her feet were hurting in her shoes, her ankle now throbbing from the slip.

"What's the use in worrying you if it's not necessary?" she finished.

"Well I don't know. Because I'm assuming the child would have been mine."

She glared up at him. "Yeah, either you or one of the other six guys."

"Once again, may I remind you that you're not funny."

"We're not together, Sherlock. Just because you sleep with me every now and then doesn't entitle you to know the ins and outs of my reproductive organs."

"No, but I could have done something."

"Like?" She tripped again. "Bloody shoes!"

"Like sitting with you while you took a test or something."

He turned them down another street, crossing along a wide stretch of cobbles.

"But that wouldn't have been–" Her high heel caught in the gap between the cobbles.

She squealed as her ankles gave way. Yet before the sound could completely leave her, his arms were around her waist, holding her mid-fall. He inhaled deeply before hooking one arm under her knees and hoisting her into a bridal lift.

"There," he said. "Now maybe we can talk without the interruption of your two left feet."

She growled as he continued to walk, carrying her down the street as if she were light as a feather.

"Fine," she said, wrapping her arms around the back of his neck. "Tell me then, what's this really about, Sherlock? Because I know you're not dragging me through London because you didn't get to hold my hand while I took a pregnancy test."

He huffed. "Mary said 'celebrate'. Like you were relieved. Like you were happy you weren't."

"Oh my god, you're offended aren't you."

"I just don't see why having a child with me is such a terrible prospect; you've done it once before and that turned out okay."

"'That' being our son?"

He rolled his eyes. "Yes."

He kept walking with her in his arms. She wondered if he was ignoring the strange looks from passers-by or if he simply did not see them.

"Sherlock, are you upset that I didn't want to have another baby with you? Or because I didn't want to have another baby with… you?"

He stared ahead for a moment. She could see his mind working behind his eyes, searching for an answer, composing it carefully before any words left his lips.

"The latter," he finally replied.

Margaux sighed, rubbing the back of his neck affectionately for a moment. "Sherlock… If I ever have another child – and it's a big 'if' – I need it to be with someone who loves me. I just… can you understand that?"

He winced at the word 'love'. But then, his face softened with understanding. It was in moments like this he knew he was hurting her. He knew that somewhere in the back of her mind she was waiting for him to tell her he was that someone. But he couldn't. Instead, all he could muster was a single word.

"Sorry."

"It's okay." Her voice was a murmur as she rested her head on his chest for a moment.

Baker Street was finally within view. The grey sky threatened to break as the harsh wind turned their noses pink. He placed her down beside him, holding his arm out to link with hers. He slowed his pace to match hers as she held onto him tight, walking down the pavement with careful steps.

"Have you ever been in love?" she asked.

He pretended to think for a moment. "No."

She felt a pang of hurt in her chest, flushing it out with a deep breath. "Do you think you ever could be?"

"I know I am capable."

She looked up at him. It was the first time she had ever heard him admit he could be human.

"I love Vaughan," he added.

"That's good to know."

"But the notion of being in love with someone. It makes it different to love. It makes it seem temporary." he paused for a moment. "When you say you're in something with someone else, that means that at any point, you, them or both of you could suddenly be out of it. The impermanence of it makes me wonder why it's worth the time."

They stopped on the doorstep of 221 as Sherlock reached in his pocket for the key.

Margaux folded her arms as she waited, looking up at the profile of his face; the curls falling into his eyes, the sharp jaw and strong cheekbones, the plush lips and the lines that deepened near his mouth.

Being by Sherlock's side had become so familiar that she sometimes forgot to look at him. Properly. She wondered if he ever looked at her this way; if his eyes ever traced the slope of her nose, admired the dimple in her cheek. He mustn't look at her this way, she thought. Because if he did, he would know there was nothing impermanent about love.

As she watched him there, all blue eyes and furrowed brow, she knew she was in it. Permanently.