“John, why are you planning to lie to the child?”
John’s eyebrows snapped together and his hands froze midair, still holding up the onesie he’d been planning to buy Rosie for Christmas. He’d said it was to be a gift from Santa and not thought anything of it until—
“Sherlock. You’re not seriously suggesting that playing along about the existence of Father Christmas is some gross violation of trust, are you?”
Sherlock crossed his arms. “Isn’t it? Teaching children that once a year a rotund man in a red suit breaks and enters via the chimney to leave behind presents for good children , which suggests he has some kind of worldwide surveillance system that would make Mycroft drool—if you don’t call that lying, what would you call it?”
“Jesus, I don’t know, Sherlock. Having a bit of fun?”
“I fail to see what’s fun about being told a lie by all the adults around you. If anything it’s a terrifying fiction.”
Sherlock gave a little shudder, and John muttered something about no wonder the two Holmes boys turned out the way they did. He grabbed the onesie in a huff and went to the queue to pay for it, Sherlock trailing along behind enumerating the ways that Father Christmas was the perfect criminal.
* * *
They were still arguing about it by the time the cab pulled up in front of Baker Street.
“It’s not breaking and entering if he’s invited, is it? You could argue that by putting out milk and cookies, parents are welcoming Santa Claus into their home.”
“Yes, but aren’t there stories of poor, abused children receiving presents despite their wicked parents’ protestations? That implies that you can’t keep Santa out even if you wanted to.”
“Well who would want to keep him out? It’s Santa .”
“It’s the principle of the thing, John!”
The rest of Sherlock’s rant was cut off as Mrs. Hudson came into the hallway to greet them. She was in a festive mood, wearing a cheerful red sweater and a fond smile, and she fussed over Sherlock and John, laden as they were with shopping bags full of gifts for Rosie.
“Better bring them in here,” Mrs. Hudson said. “Don’t want to ruin the surprise.”
John was about to point out that Rosie was only two and probably still too young to go looking for hidden Christmas presents, but even Sherlock didn’t say anything, so he let himself be ushered into Mrs. Hudson’s apartment.
By the time they left—without the gifts for Rosie, which they’d agreed to let Mrs. Hudson hang onto—they were full of freshly baked pumpkin bread and delightfully buzzed from some wicked eggnog, and John had forgotten all about the ridiculous Santa Claus argument.
* * *
Which was why, when John woke up to find a tall, slender man in a white beard and a red coat skulking around the flat before dawn on Christmas morning, his first instinct was to tackle him.
“John!” The figure under him yelled, and even muffled by the carpet, John would have known Sherlock’s voice anywhere.
“ Sherlock ?” He let him up, incredulous. “What in God’s name are you doing?”
Sherlock got up with a huff and leveled an affronted glare at him. Sherlock had a scowl that could leave the most hardened men of Scotland Yard quaking in their boots, but the effect was quite ruined by the ridiculous polyfiber beard. John took one look at him and started laughing, and once he started he couldn’t stop.
Sherlock huffed, “Really, John,” and it just made it funnier.
“Oh God, Oh God,” John gasped between fits of howling laughter. “The hat !”
“You’ll wake Rosie,” Sherlock hissed, as if that made any sense at all.
It was a few moments more until John was able to get a hold of himself, until he was wiping the tears of mirth from his eyes and finally able to speak again. God, he hadn’t laughed that much in… he couldn’t remember when.
“Sorry? Wasn’t Rosie seeing you the point?”
“Of course not!” Sherlock snapped, apparently still put out by how funny John was finding this whole endeavor.
“What? Then what on earth are you doing sneaking around wearing that at four in the morning?”
Sherlock fidgeted, clearly uncomfortable. “You seemed to think that believing in Santa Claus ,” Sherlock said the word like other people would say flesh-eating bacteria , “is a crucial component of a happy childhood. You’re the expert on such things, so I thought—” he gestured at the presents he’d been in the process of leaving under the tree, the dish of cookies that was now empty but for crumbs. Sherlock— Sherlock who after all these years still ate only when John made him—had eaten cookies for Rosie. To give her a happy childhood.
John’s heart swelled with an overwhelming fondness for this madman. He grinned.
He couldn’t help ribbing Sherlock about it.
“You were going to make believe about Santa!”
“Yes, well. Obviously you needed help. Were you just going to tell her Santa was here? Absurd.” Sherlock sniffed. “Clearly she’ll take after me. She wouldn’t have found the idea believable if there wasn’t physical evidence that Santa had broken in. A white beard hair here, a thread of awful red polyester there—”
“You realize Rosie isn’t your biological child, right?”
Sherlock flapped the idea away with a hand as though it was preposterous. “Nature versus nurture, John. We’re raising her together, of course she’ll take after both of us.”
John pulled down that ridiculous costume beard and kissed him.
(He was so glad Sherlock didn’t know enough about pop culture to tease him with “I Saw Mommy Kissing Santa Claus.”)