Something about the enthusiasm with which Sherlock prepared for the ball themed 'Blood and Death' raised John's alarm. It wasn't exactly in Sherlock's nature to prance around all excited about his outfit, though fitting as it may be, as the pale man played the part of a vampire quite spectacularly, with his cape and all.
Sherlock had insisted that John should find something equally suitable for the occasion, as it wasn't an everyday occurrence for them to be invited to the ball held by the high and mighty Marquis deSade, no relation.
So John had worn what he wore best - the outfit of a soldier, with minor changes, such as the bottle of holy water and some stakes looped to his belt, a huge cross in his hand to ward off all evil, which caused a minor ruse when Sherlock took it upon himself to get annoyed by John's antics, belaying all Sherlock's intentions to muss up John's carefully applied mask.
After a minor scuffle which ended in a teasing kiss, the pair was ready to go, and as expected, the cabbie taking them to their destination didn't spare a single look for his customers. Today, nothing was too odd, even by London's standards.
Upon arrival John nearly lost his footing as nothing had prepared him for this; High up in the curving ceiling of the hall hung a chandelier the size of a bathhouse tub that would fit two people and still left room for a bit of frolicking, the marble water fountain standing in the middle of the hall featuring a seashell which upon stood what had to be two men entwined in a heated embrace, the windows draped with velvet, cinctured and folded into heavy, dark green waves, the entrances to adjacent rooms all closed off from the visitor with French doors with even more of the luscious fabric.
Paintings, detailed candlesticks, mosaic pattern laid into the floor leading to the one room that had the doors opened and the head of the house standing in the doorway with a friendly smile on his face and his hand extended in a greeting.
Stepping inside the mansion from the encompassing darkness of London night, Sherlock blinked blindly at the brightness of the hall and promptly, yet discreetly nudged an elbow into his companion's ribs before said companion could drop his jaw hanging even lower.
"Smile, John, and nod. Smile and nod, whatever he says, whatever I say, and try not to stare at the fountain. That will probably be the most innocent thing you'll see here on this fine evening."
Thanking his luck his grin wasn't out of place, although the reason for it was less pure than the onlooker could assess, what with seeing John getting slowly but surely flushed with the sight of such art, Sherlock's grin itself only seemingly showed the joy of being reacquainted with an old friend. Not that the old friend would've particularly mind a bit of lechery being displayed right then and there…John, on the other hand, would very probably object.
That, and the 'old friend' wasn't really a friend at all.
A thought flickered at the edges of Sherlock's mind, enough to make him feel a stir of nervousness in his chest, but not enough to grasp the thought and recognize it. So he promptly ignored it.
"And what brings two fine gentlemen to my humble lodgings, sirs, if not the irresistible call of rarities never to be found anywhere else," came a cheerful call from the doorway.
"Take a step, take another, and come forwards and introduce me to this delectable young man you have brought with you, Sherlock Holmes, do not shy from presenting such treasures."
John's eyes darted up and widened at the words, the elaborate surroundings, and indeed the fountain suddenly being the least of the reasons he was now utterly pinkish all over his ears, thankful of the make-up covering the blush underneath.
"Ah! Marquis!" Sherlock called out cheerfully scandalized and placed a hand flat on John's back pushing him gently to coax him into moving and perhaps for a little reassurance.
The introductions made John feel slightly out of place, the host's eyes roaming along John with a clearly approving smile, complete with a wink directed at Sherlock, who only smiled charmingly, seemingly proud of the Marquis's approval.
As the pair finally got further into the mansion, Sherlock was halted by many a 'whatsherfaces', with whom Sherlock chatted jovially, introducing John as required, until John's discreet eye roll at the thirty-second 'enchanté, cheri.'
Whispering into John's ear, Sherlock prompted John to look around, to keep a keen eye on anything suspicious, in that tone which promised secrets and revelations. Tone, to which John had come accustomed to in the first months of their acquaintance.
Roaming through the rooms offered very little of interest. Faces blurring into other faces, shallow chatter filling the air, a few stray, uninterested glances at John's direction, and John saw it far more interesting to roam down through the cellar door, onto a corridor lined with wine racks, and further down, where his heart stopped and his breath forgot how to function.
Although Sherlock had briefed John for the upcoming events, nothing could have prepared him for this. Not this, not even in his wildest, sickest nightmares.
Rushing back upstairs, frantically searching for Sherlock, John bumped into the other guests, earning disapproving murmuring all around him, until he found his companion, and dragged the perplexed man into the restroom.
Pacing around like a caged animal, trembling, horrifying images flickering in front of his mind's eye, John checked that there was no one else in the room, before he began his interrogation with his voice parched; "And when were you going to tell me about the children Sherlock?" John grabbed Sherlock's arm as if preventing him from fleeing. Sherlock, for his part, stood there stoically, knowing perfectly, understanding, before John could elaborate.
"All in good time. Soon." The grave tone in Sherlock's voice convinced John of his sincerity, so he let go his hold and slammed his hand next to Sherlock's head to the wall, making a frustrated fist of it.
"The children in the basement." John stared at Sherlock coldly. "The children that, by the look of their bones, have been there for some time." John shifted closer, challenging, on the verge of pure rage. "Dead children, Sherlock, skeletons. 'All in good time?'"
"It wasn't time yet. There's no telling what you'd done if you'd come here knowing. All my work here would've been moot."
"So you pretend, the master of disguises, to mingle with these people, mask yourself as their friend. How can you do that?" John's voice was low, threatening, filled with the urgent need to do something, anything.
"And that, as you may have guessed, my dear fellow," Sherlock closed the gap between the men, something akin to sorrow in his eyes while he raised a hand to cradle John's face, continuing; "is how I've spent years infiltrating into this secret little society. And now I have you here with me."
Slowly, John's façade broke to a fragile, small smile, understanding arising. "And together we will bring these bastards to justice, is that your plan?"
Sherlock nodded, "We're close. Closer than I've even been by myself. There are risks still, and I still don't have all the facts, no scope of the magnitude, but we're in on a good start."
Solemnly, Sherlock gathered John's hands between own; "This might kill us both."
"Well," John shrugged, his smile never wavering, already readjusting himself to fit back in with the crowd outside. "At least I get to do that by your side."
Together, the consulting detective and the doctor headed out the room, smiles in place, keen eyes inspecting anything and everything, to finally find the last nail to pound into the Marquis's coffin.