Sherlock is certain that he knows everything about babies. He knows their brain development patterns. He knows when babies typically start teething and crawling and walking and speaking. The information has been invaluable on a surprisingly large number of cases. Most memorably, a kidnapping case that ended with Sherlock deducing that the child had recently started walking and the mother was unaware. The child had walked away from the house and was sleeping nestled among the tall grass and wild flowers that covered the property. He hadn't even needed to see the scene.
When John moves back into 221B with his infant daughter, Sherlock concludes that he knows absolutely nothing about babies. At least, nothing that will help him with the practicalities of living with one every single day. How does John's daughter manage to get so dirty when she can barely even lift her own head? Why won't she stop shrieking? Does she actually hate Sherlock or is she just testing out her new glaring skills? How is it possible for this tiny human to remind him so much of John? Why does that reminding open a sharp chasm in his chest? How can he miss a man who lives in the same flat? Surely this feeling can't possibly be connected to the phantom pain consuming his chest where the bullet wound has long been healed?
Several weeks, maybe a month (? Sherlock lost count), after John moves back in, finds life much the same as it has always been at Baker Street. Sherlock Holmes and Dr. Watson are taking cases again. Mrs. Hudson is still serving tea and making dinners while stubbornly reminding them she is not their housekeeper. Mycroft rarely visits, for which they are all grateful. Lestrade becomes a semi-permanent fixture on their staircase, rarely making it all the way inside the flat before the duo is flying down the stairs hot on his heels.
For all that things have stayed the same, 221 has seen a few major changes. Baby gates lean against the walls, waiting to spring into use the moment the baby starts crawling. All the sockets have been baby-proofed and the sharp, weapon-like objects have been placed out of reach. Sherlock still performs ghastly experiments, but he knows the time is coming where he will no longer be able to store corrosive acids or biohazards in the flat. Not when a curious child could find them at any moment.
A shrieking wail cuts through the usual serenity of the early hours. Sherlock sighs and rises to get the baby before she wakes John. John hasn't been sleeping well, and Sherlock hopes he can manage a few more hours at least. As Sherlock enters the nursery, the baby's eyes go wide and her mouth opens in an "o" of surprise. Sherlock chuckles.
"Should've known to shock you into silence. After all, it's worked on your dad quite a few times, hasn't it?"
Big blue eyes blink back at him. As Sherlock reaches into the crib to pick up the child, her face contorts in displeasure and he can see the oncoming strop. He raises his hands in surrender and backs a few feet away. This seems to pacify the baby who becomes much more interested in the floating mobile overhead. Sherlock sighs in relief and studies her carefully.
John wakes in a cold sweat. He just can't seem to shake these nightmares. He automatically blames Mary and feels the guilt overwhelm him. He knows the guilt is misplaced. She is the one who lied, but he still has a hard time blaming his dead wife for the trouble. He rolls onto his back and scrubs a hand through his sodden hair. He'll need to take a shower before the baby wakes up.
John squints an eye at the clock on the bedside table and is surprised to find that it's half-four in the morning. She should be awake and screaming for a bottle right now. Fearing that something is wrong, John throws the covers off of himself and prepares to spring out of bed, when he hears a soft murmuring coming from the baby monitor. He lies back down and rolls to the other side of the mattress, closer to the monitor. He carefully dials up the volume and listens. Sherlock's deep baritone is unmistakable and shockingly soft.
"What is it, little princess? You can't even lift your head yet and you hate me. Takes most people longer than that."
Sherlock whispers conspiratorially. John's heart drops at the implications of that statement.
"Yes, you. I've seen the way you look at me when you think I don't notice. You must have John's natural mental acuity to see the truth so quickly, Ms. Smartypants."
Sherlock feels a lump rise in his throat as the baby burbles at his gentle teasing. It's the first non-screaming, positive reaction he's gotten from her. He risks approaching the crib again, and this time, the child eagerly waits to be lifted into his arms. He nestles her close to his chest and sits in John's armchair which has been requisitioned for this exact purpose. He leans back and inhales deeply. The scent of John still lingers strongly in the fabric. He must actually sit here a lot. Sherlock misses the chair in the sitting room, but he can't deny it's utility now. He leans forward and murmurs into the baby's sweet-smelling wisps of hair.
"I don't think John wants to stay here, little one. He's always on edge, and my presence makes everything worse. I wish he'd stay though. Both of you. I know people don't think me capable, but I love you both very much. So very much."
He mutters the words like a mantra against smooth newborn skin. What is it about baby scents that is so calming? Surely, he used to know this?
John is paralyzed for a moment by the enormity of what he's just heard. He had thought they were a bother, a burden to Sherlock's chosen bohemian lifestyle. Did he really just hear that correctly? Sherlock doesn't merely tolerate their presence but actively wants them here. Both of them. He loves them? Us?
In the next moment, he is out of bed and flying toward the nursery with the monitor still clutched in his steady left hand. He stops just outside the door, not wanting to race in and scare the baby. John takes a few moments to settle his breathing, and he feels his courage dropping.
"Come in, John. She's asleep."
John can do nothing but obey. The unexpectedly domestic scene punches through him. Sherlock, sleep-rumpled and soft, is seated in his armchair holding his infant daughter against his chest while she sleeps. John thinks he might have to invest in an oxygen tank for the flat if his lungs insist on acting up so frequently. He walks over to the chair, sets the monitor on the table, and perches on one of the arms.
John's arm rests casually along the back of the chair to keep his balance. The contact with Sherlock's skin is just an added benefit. The detective's head is tilted back, resting against the back of the chair, and his eyes are closed. Unfortunately, this reveals a long expanse of milky white skin that makes John clear his throat deeply before he begins speaking.
"I heard you, you know?"
Sherlock doesn't move and seems partly asleep. His only response is a rumbled,
John shifts closer, taking some pressure off his bad leg.
"Um, I mean through the baby monitor."
Sherlock's body stiffens but he manages to blink his eyes open slowly, as if he is only perturbed for being roused from his sleep.
The retort is caustic, but John is prepared.
"And I think you are theorizing without all the data,” he whispers.
Sherlock turns to look up at him and realizes their faces are only a few centimeters apart. John nods and Sherlock can feel his breath gusting across his cheek. Screwing up his courage, he cocks his head and lets his eyes soften to a more truthful kaleidoscope of emotion.
"Then by all means, correct me, Doctor."
John raises his free hand and traces the shadows and moonlight playing over Sherlock's face. He spends careful minutes tracing every line of that elegant face. He has wanted this for so long, and Sherlock doesn't seem inclined to stop him. As John is thumbing over Sherlock's plush mouth, the man parts his lips and speaks.
The word is imbued with awe and concern and hope. John leans forward, maintaining eye contact with Sherlock until they are breathing the same air. Sherlock's eyes are full of undisguised fear.
John asks, wanting verbal confirmation of their mutual desire. He watches Sherlock's adam's apple bob as he fights to verbalize a response. When it comes, it is a sigh so soft that John could almost believe he imagined it if he didn't see the word radiating from every pore of the man's angelic face.
Their lips press together lightly. Time expands and hovers over them, suspending them in this moment. Hours, minutes, days could pass, and yet they would be here in the darkened nursery twining together in John's armchair with their child nestled between their chests. Gentle, protective, and loving each other unconditionally, always.