Once upon a time, there was a kingdom ruled by a man named Lestrade, who was renowned for being fair and just and kind. King Lestrade had twelve daughters, and it was said that each one was more beautiful than the last, no matter which order you counted them in. That was a bit of rubbish, of course, but the girls did all range from moderately to very attractive, which meant it was hardly the worst lie ever told. Besides, King Lestrade was as fair and just and kind as he was famous for being, so all told the people were quite well satisfied with the state of things. And, as is inevitably the case when everyone is well satisfied, that was when everything went wrong.
The problem, put succinctly, was shoes. With twelve princesses, it was hardly surprising that there would occasionally be some issues with shoes, especially given the third youngest's, Janine, extreme fondness of them, but this was a bit beyond that. Every morning, the dancing slippers of all twelve princesses would be tattered and worn through. Every day – for fear that damage done to replaceable shoes might be done to less replaceable feet otherwise – twelve new pairs would be made, only for them to meet the same fate the next morning. Now, while the price of twelve new pairs of dancing slippers might only be a pittance to a king from such a prosperous kingdom as King Lestrade's, twelve new pairs a day was rather more expensive. King Lestrade explained this to his daughters and implored them to stop ruining their shoes, or to at least explain why they felt the need to dance the night away, but not a single one of them offered a word of justification. (It might be noted, though whether it was relevant or not was debatable, that the second youngest, Molly, looked near tears in her refusal, while the second eldest, Irene, seemed to find the whole thing vastly amusing.)
Unable to think of another way to stop the nightly shoe destruction, King Lestrade ordered all the princesses ousted from their bedchambers and instead made to share a room that was large enough for twelve beds, twelve wardrobes, and twelve vanities, but not large enough to also contain twelve dancing princesses. Then all the entrances and exits to the room were closed off, save a single heavy wooden door. That door was refitted with a single heavy iron lock that in turn could only be opened with a single heavy iron key that King Lestrade never removed from a chain around his neck. (Anyone who has ever tried to sleep with a heavy iron key around their neck can attest to how very dedicated to his daughters King Lestrade must have been in order to do so.) But despite these measures, the King still found himself buying twelve new pairs of shoes each day.
Truly desperate now, he opened up a challenge to anyone who cared to take it. Though, after an incident where the middle daughter, Sally, proved the worth of all the lessons in self-defense she had insisted on, and the third eldest, Sarah, proved the worth of all the lessons in medicine she had insisted on, the wording was changed to 'anyone who cared to take it that wasn't a known murderer, rapist, or thief.' This person would be allowed three nights locked in the room with the princesses. If at the end of that time, they were able to reveal the truth behind the princesses' nightly activities, then that person would have a great reward bestowed upon them, the exact nature of which was rather vague. There were rumors that the reward was the hand of one of King Lestrade's daughters, rumors that surprisingly weren't dispelled after it came out that the first challenger had been the princesses' nursemaid/nanny/governess/all-around mother figure, Mrs. Hudson. Other rumors suggested that the winner would become King Lestrade's heir, but anyone who knew the eldest daughter, Mary, knew that the title of heir apparent would only go elsewhere over her dead body, quite literally. (And truthfully, even if someone did get past her, they would suddenly find themselves contending with the youngest daughter, who was currently going by Anthea.)
Despite, or perhaps because of, the mysterious nature of the reward, many came to take the challenge. There were princes and paupers, dukes and destitute, and one particularly enterprising young goose girl who eventually went on to have a fair number of adventures of her own, but each one of them failed to uncover the truth behind the ruined slippers. And with each failure, King Lestrade fell a bit more into despair.
AN: Here's where I issue a challenge of my own, 'cause I'm bored. As I'm sure you've noticed, John, Sherlock, Mycroft, and Moriarty have yet to show up. If someone can correctly guess the roles all four take in this story, I will fill any request that person has (so long as it's not explicit, because there are limits to my abilities, guys) in any fandom I write in. Ready, go!