Yay, another chapter! This is one of my favorites and is sort of crossover-y. It also has elements of another fic I've been working on (and I probably should've posted that one first. Oh, well. When I do get it out, I'll update this author's note).

I don't own Kuroshitsuji, BBC's Sherlock, or "Night Vision," "We Are Giants," and "Swag," which are products of the wonderful Lindsey Stirling! If you haven't, go listen to those three songs as you read this fic- they're described in the story and are kind of essential to it. You'll get the full experience if you listen to them.

Like, comment, review, no flames or profanity please!

Sebastian poured a cup of Earl Grey and handed it to Ciel, who took it and sipped as he read a sleek pamphlet. "A musician's competition?"

"Well, since you're so good at the violin, I thought I might have you enter. Should be entertaining, don't you think?"

Sebastian raised an eyebrow as he cut a slice of cake and served it to the teen. "Is there some sort of ulterior motive you have in attending this competition, my lord?"

"Yes, actually, as a matter of fact." From his breast pocket Ciel produced a letter adorned with a black seal. "Mr. Spears requested that we investigate this individual. Apparently he appeared out of nowhere and entered the contest as a violinist. The Grim Reaper Association is very alarmed at his presence, and our job is to find why he's really here."

The ravenette accepted the file Ciel offered him and scrutinized its contents. His eyes fell on a photograph of the man in question. Interesting. Tall, pale skin, dark curly hair, pale eyes, thin nose, cupid's-bow lips, slender body, feminine hands. Dressed like a gentleman, but he doesn't look very comfortable in his clothes. He read the name listed at the top of the page. "William Sherlock Scott Holmes? That's a rather odd name; I wonder if our dear Arthur was inspired to name his protagonist after this man."

"That's the problem: Mr. Holmes didn't even exist until just recently. Arthur couldn't have gotten the name from him."

"I don't understand. What do you mean, he didn't exist? Surely he must have just been on the run and created a new identity for himself—"

"That's what I thought at first, but then I read the rest of the file."

Sebastian frowned. "Age: twenty-seven years old. That's strange, the date of birth has been left blank. But if the Grim Reapers don't know his birthdate, then how do they know his age?" He leafed through the rest of the file. "His family members' ages and birthdates are missing as well. In fact, all of the dates are missing from his file, except for the ones at the very end. I suppose those are around the time he caught the attention of the Reapers?"

"That's not all." Ciel handed him the letter. Sebastian took it and read it.

"They say his file isn't supposed to exist yet— wait, not supposed to exist yet? What on earth?"

Ciel rested his chin on his folded hands, elbows on the desk. "All but the most recent dates are missing… that must mean that those dates haven't happened. In that case, the man hasn't even been born yet. I believe it's safe to say that he's a time traveller from the future."

Well, that explains why he's unaccustomed to those clothes, Sebastian thought. "And so we are to uncover his reason for arriving at what would be the past for him. Perhaps some great calamity occurs and he's come to stop it?"

"Or to ensure its success. That's why we need to enter in the competition. I'm not good enough to pass, but you could easily win. After you enter, you need to get close to him and find out what he's up to."

Sebastian bowed. "Certainly, my lord. I will not fail you."

This is a bit reminiscent of the curry competition, isn't it?

Sebastian stood backstage, tuning his violin and listening to the other performers' chatter. A total of eight people, including him, had entered the contest: two pianists, a cellist, an opera singer, a flutist, a harpist, and of course, the mysterious Mr. Holmes. The latter sat in a dark corner, his features cast in shadow. Seizing his chance, Sebastian walked over to the man and offered his hand. "I don't believe we've met before. Mr. Holmes, is it? My name is Sebastian Michaelis."

The man stood and shook his hand, his eyes narrowed. He spoke with a smooth, musical baritone voice. "You are correct; my surname is Holmes. Pleasure to meet you, Mr. Michaelis."

"Oh, do call me Sebastian. We are fellow musicians, are we not?"

"Indeed. In that case, you may call me Sherlock."

Now that Sherlock was out of the shadows, Sebastian noted that the photograph hadn't quite done the young man justice. His dark locks glinted with a hint of brown, and his skin glowed like creamy porcelain. The faintest blush of pink colored his full lips, and his lashes were long and dark. But oh! those eyes! They sparkled like magic, the pupils rimmed with gold and green and surrounded by crystalline blue, a small speck of brown above the pupil of the right eye. Sebastian gazed into those eyes and knew: this man was very special. And it's not the fact that he's a potential time traveller; there's something unique about him, but I can't put my finger on it. How odd.

"So! What do you think? Is this your first music competition?" the young butler asked in an attempt to make conversation.

"Hmm. Competition, yes, although I have showcased my music before. I'm a bit curious, though, as to why a butler like you is competing; your master doesn't seem to need the money."

Sebastian stared at him. "My, you're certainly observant."

Sherlock scoffed. "It's my job to be observant— I'm a consulting detective. The only one in the world, in fact. I invented the job, after all."

"So you're a fan of Arthur Conan Doyle, then? You're doing an interesting impression of his protagonist, if I may say so myself. Am I to assume that 'Watson' is somewhere in the crowd and this is all part of a case?"

The brunette gave him a strange look, and Sebastian swore he turned deathly pale. "Sherlock? Is something the matter?"

"No, I'm fine. I just realized something just now, that's all."

Sebastian opened his mouth to apologize, but one of the pianists called out to them instead. "Oi, you two! We're supposed to be out there!"

The two men rushed over and followed him onstage.

"Ladies and gentlemen, I present to you the contestants of this year's Classical Performance Competition!" said the announcer as the performers filed onstage. Sebastian and Sherlock stood next to each other and waited for his speech to end. "First up, we have Gerald Simmons on the piano!"

The two waited backstage as the others performed, one by one. Finally they heard, "Next up, Sebastian Michaelis on the violin!"

Sherlock gave him a small smile. "Merde," he murmured. At Sebastian's confused frown, he chuckled. "It means 'good luck' in the ballet world."

"I see. Thank you." Sebastian smiled back.

As he came out onstage, he thought, I will win, young master. You have ordered me, and I will follow your order.

"Amazing! Truly beautiful! A masterpiece!" the announcer exclaimed after Sebastian's solo. "And the judge's scores are in! A perfect ten!"

While Viscount Druitt babbled on about his performance, Sebastian slipped backstage. "And finally, performing on the violin, Sherlock Holmes!"

The audience whispered in bewilderment. "Sherlock Holmes?" "Are you sure that's what he said?" "Is he like the character in Doyle's stories?" "What's he doing here?"

"Good luck," said the ravenette as the young detective passed him. "You're going to need it."

Sherlock ignored him and went onstage.

Sebastian and the other performers crowded around and peeked between the curtains, waiting anxiously for Sherlock to start. His perfect solo had left the young demon very confident in himself, and he suppressed a smirk. He seemed to know the basics of playing the violin. I don't know how much experience he has, but I doubt he'll be able to best me. That is, unless he's lucky.

Sherlock exhaled a small breath. He plucked a couple measures of notes on the strings, then laid his bow on them and began to play.

Sebastian blinked. The music pulsated and was nothing like he'd ever heard before. And who's performing the percussion? I'm certain he's not the only one playing! A single violin can't possibly put out all that!

The music softened— he was plucking the strings again— then got louder, and his playing became more passionate. He moved his whole body as if the music was in control of it. Just as the music crescendoed, it turned extremely rhythmic, and his dancing (for that was what it was) became stiff and sharp like an automaton, interspersed by smoother bits. Then came a part with some very fast and tricky fingering, but Sherlock played it flawlessly, all the while smiling with joy. He plucked the strings some more, then replayed the beginning section, with some variations. Now he was at the passionate part again, and Sebastian bit back a gasp as the auditorium darkened. The judges glanced at each other, unsure of what was happening.

Then Sherlock's violin began to glow a sharp blue, and as he pirouetted, the young butler caught a glimpse of his eyes— they were glowing blue as well! He continued to the rhythmic section, and Sebastian found himself both mesmerized and disheartened. There's no way I could win the competition now. I must have underestimated him— but what if he's using black magic? But the energy emanating from the brunette was far too pure and bright to be dark magic. As he played the difficult section and finished with some more plucking, Sebastian shook his head. Someone's helping him win.

After he finished, the auditorium returned to its normal lighting. The audience sat in shocked silence for a moment. Then they leapt to their feet with thunderous applause! Sherlock smiled and bowed.

"What strange tones! But so beautiful!" Viscount Druitt cried. "The notes are like shining stars in the night, twinkling brightly as they look down from the heavens! The melody is like the moon, guiding the listener to the performer's heart! What soulful strains! What fascinating beats! This, this is the beginning of a new era of music!"

"A straight eleven! It appears as though young Mr. Holmes is the winner of our competition! Congratulations, sir!" The announcer shook Sherlock's hand. "Pardon me for asking, but wherever did you hear such music?"

"Oh, I didn't learn it from anyone," Sherlock replied. "I was only following the notes of my heart."

Sebastian frowned. I will find out his secret and expose him.

Afterwards, Sebastian had packed up his violin and met back up with Ciel outside the theatre. "Well, Sebastian? What do you think?"

"To be honest, my lord, that was quite a performance on Sherlock's part. He certainly went to a good deal of trouble to win the prize money that I find it a bit odd."

"Is that what you thought I was here for?" The two whirled around to find the young detective standing behind them. He tsked. "I have no need for money. Really, Sebastian, I thought you were more intuitive than that. How disappointing that you're not."

Sebastian opened his mouth to retort, but angry shouts cut him off. "'Ey! It's the bloke who won the contest! Get 'im!" The cellist and one of the pianists charged towards Sherlock, who tossed the sack of prize money at their feet. They stopped and stared at him.

"What the hell?!"

"That is what you wanted, yes?" Sherlock replied. "You're angry at me for winning the competition because you so desperately wanted the prize. I have no interest in it— you might as well take it."

The men sneered at him and pulled out loaded revolvers. The brunette took one look at them and, violin case still strapped on his back, bolted.

"After him!" the men cried and chased him down a nearby alley. Sebastian glanced at Ciel.

"My lord, your orders?"

Ciel lifted his eyepatch, exposing the pentagram on his right eye. "Apprehend him for questioning, Sebastian. That's an order!"

Sebastian bowed his head. "Yes, my lord." Then he took off in pursuit of the young violinist.

As he ran, he heard music of the same strange style as what Sherlock had played in the competition. Someone's singing, too. I can sense the same exact bright power that flowed from Sherlock when he played. Is someone helping him escape? He leapt up and ran along the top of the buildings, always keeping the young detective in his sights. At one point Sherlock's pursuers lost sight of him, but they continued after him. Then Sherlock reached a busy street and stopped. He looked around, clutching his case strap over his chest, his face full of fear, and proceeded to cross the street, dodging and ducking out of the way of carriages and cars. Then his chasers arrived and foraged their way towards him. The young man slipped into an alleyway just before they could catch him and ran until he came upon a dead end. He skidded to a halt and whipped around to face his pursuers, who had accumulated to about ten men, all burly and armed with different guns.

Sebastian reached the building to Sherlock's right and stood ready to leap in front of him to protect him. But instead of pulling out a weapon, he slung his case off, bent down and opened it, and retrieved his violin and bow. The atmosphere vibrated with magic and music, building and rising, and Sherlock's eyes glowed with the same eerie light as before.

Then he began to play, and the air burst with sound and light and energy. Sebastian froze in shock as a bubble of light formed around the dancing musician. The other men shot at him, but the bubble shielded him and reflected their attacks. Slowly he levitated and rose up out of the alleyway and over the buildings, streams of light and melody emanating from his shining heart and spreading out over the city. The youthful demon could only watch, entranced by the display of sheer beauty and power surrounding the young detective.

I don't understand— is this all his doing? Are these his powers I'm witnessing? Is this what makes him so special?

Sherlock floated down on the roof and finished playing, the music and light fading away. The men in the alley dropped to the ground, unconscious. Sebastian stared at them, then back at the brunette, for once rendered completely speechless.

"You have questions, don't you."

The raven butler blinked and nodded. "Then perhaps you could lead me to a place where we can speak in private?"

"I-I… Yes, yes, I can, I… Do you mind if my master is there?"

"He's the one behind the investigation, he might as well join us."

Sebastian nodded again. "Very well, then. Follow me."

The trio, along with Will Spears, Ronald Knox, and Grell sat in the Undertaker's parlor with beakers of tea while the Undertaker munched on biscuits. Will adjusted his glasses with his pruning shears. "We haven't got all day, Mr. Holmes, so if you would be so kind as to hurry it along—"

"I'm a Heartsong."

The dark-haired Reaper raised an eyebrow at the interruption. "I beg your pardon?"

"A Heartsong? What is that?" Ciel asked. Sherlock glanced at the violin case and sighed.

"A Heartsong is a person— a musician, really— whose heart produces melodies of immense power. When the Heartsong plays these melodies, he releases this power out into the real world, and the music sounds exactly how he hears it in his heart. Often his powers transport him to otherworldly places and scenarios or protect him and others from danger, like the piece I played when I was trying to escape from the men who were after me. Other times, the Heartsong uses his magic simply for the enjoyment of his audience, which is what I did at the music competition."

"Are you saying you could have played something different and not used your magic to win?" Sebastian exclaimed.

"I didn't use it to win; in fact, I didn't need to. The thing about a Heartsong's power is that the Heartsong has no idea when it will activate. It's very difficult to predict these instances. Sometimes his emotions trigger his powers, sometimes his situation triggers them, and sometimes they're triggered when he's in danger. I think that I could have played without them at the theatre, but something in my circumstances activated them and I was swept along in my music."

"So my excellent playing must have done that," Sebastian mused. "Do you think your powers forced you to travel through time?"

Sherlock nodded. "Yes. A dear friend of mine, a fellow Heartsong, decided to play some music from a Japanese show called Black Butler and invited me to join in. We played three songs together, our powers activated, and after the third song, we both fell into this world. She deduced that we would have to play three songs in the style of our time in order to make it back. She was able to leave; I, however, have not been able to yet."

"And you need your magic activated in order for this to work? You can't just play this music normally?" Ciel questioned.

"I'm afraid so. Victoria managed to use her powers almost immediately and played the songs in quick succession. Unfortunately, her music didn't make its way into my heart, and now I'm stranded here until my magic triggers again."

"And you have one more song left to play, correct?" inquired Will. "And you need something to activate your powers."

"That's right. I wonder… perhaps I could play for you all and see if that works." Sherlock took out his violin and bow as the others made space for him and sat along the edges of the room on coffins.

The moment he touched his bow to the strings, beautiful music spilled out into the room. His eyes lit up with joy, and he danced, the melody and beat in full control of his body. Everyone gazed on, enraptured. As he continued, the floor began to glow around him, and when he finished, he vanished in a flash of blue light.

Undertaker spoke first. "Goodness me, he's the most amazing Heartsong I've ever heard! I wonder who'll be the lucky Reaper to come get him when it's his turn to die?" He chuckled. Grell rolled his eyes.

"He's the only Heartsong you've ever heard, Undertaker."

Undertaker held up a finger. "He's actually the third."

"Oh?" Will frowned. "I've never even heard of them before."

"They're extremely rare, you see. They were a little more common back in my day, but any young Reaper who was assigned a Heartsong's file had the privilege of listening to their wonderful music through their cinematic records. I was very, very fortunate myself— assigning two Heartsongs to a Reaper was unheard of!" He chuckled again. "Those two were amazing, but that young man outshone them both! Hee hee! He's probably the most powerful one to date! And he's got a Heartsong soulmate, from the looks of it!"

"Hey! His file is missing!" Ciel exclaimed. Sebastian glanced down at the teen, who held the envelope that had contained Sherlock's file— only now it was empty. Undertaker shrugged.

"Guess he made it back to his time period, then, eh?"

As they left the funeral parlor, Sebastian couldn't help but sigh wistfully.

I wish I could be a Heartsong like him.