Authors Note:This oneshot is based on two things - the 'Constancy of Music' voxophone from the new DLC, and Rosalind's brief piano playing after you crash the airship in the main game. I always liked that little moment, and once I heard the new voxophone this idea was brought to life. It's also partially based on an idea I cut from my earlier fic, What's Done Will Be Done, so I'm glad I got to write that out fully as part of this snippet!

As ever, please leave a review! Comments, criticisms and questions are warmly recieved. Thank you for your time.

Disclaimer:Robert, Rosalind, and all related ideas are property of Irrational Games. I'm just borrowing them for a bit, honest!

Perhaps A Waltz, Brother?

It was the eighth of October, 1893. The sun rose, warm and bright, above the floating city of Columbia. And inside her makeshift lab, Rosalind Lutece was changing the course of human history.

The wall shimmered. A window opened. Two men stepped through realities, travelling in an instant across the boundaries between their worlds. One stood, clutching a wailing child to his chest. The other fell, hitting the floor hard with a sick thud.

That was almost a month ago, and her brother had only gone from bad to worse in the meantime. She knew what was causing it – they had both suspected that permanently crossing realities was going to have its hazards, not to mention the fact that such travel was completely unprecedented and mostly untested. Still, in all their preparations and experimentation, they hadn't foreseen something like this happening.

She had met Robert while she was testing an invention of hers – the Lutece Field, a machine that kept particles suspended in space and time. One day, the particle she was observing began acting erratically, displaying a message in Morse Code from a man claiming to be doing the exact same thing as her.

Them being scientific genii, it hadn't taken long for the pair to work out what had happened. Somehow, the Lutece Field allowed them to communicate across separate realities. Robert and Rosalind were the same person, separated only by a single chromosome – and the seemingly impenetrable barrier between their realities.

It wasn't long before they began working to fix that. They were both brilliant physicists, with a will of iron and a determination to meet each other. It may have been a challenge, but it was one they were definitely up to.

And now, with some aid from their rich benefactor, they had succeeded. Robert was there, right in front of her. She could see him, speak to him, be in the same space as him. She was elated; that is, until he had collapsed, haemorrhaging blood from the nose.

Apparently, her reality didn't take kindly to having two Luteces inhabiting the same space. Robert's mind was altered by coming into her reality, and she didn't yet know if the change was permanent. It wasn't something she really wanted to consider. Anyway, her main priorities were focused towards more pressing matters; primarily, getting her brother to stop bleeding all over her new lab.

They had tried everything to heal him. After the first day, she had persuaded Comstock to bring in some of Columbia's better doctors to see if they could find some mundane way of helping him. Besides stemming the worst of his bleeding, however, they found themselves able to do little, leaving after an hour with a collective shrug. Rosalind wasn't surprised. As if she could expect those imbeciles to understand the delicate nature of inter-reality travel.

After that, her efforts to find some sort of solution had intensified. Some quick recalibrations of the Lutece Tear proved futile. There was apparently no way she could use that to stabilise him in this reality – not that she could find, anyway. Similar reimaginings of previous experiments were just as useless. Until she could find something better, all she could do was keep him safe and monitor how he was as she worked.

Yet despite all of her efforts, her ersatz brother was only getting worse. He was bleeding almost constantly now, necessitating far too many emergency transfusions of her own blood just to keep him stable.

That wasn't the worst of it, however. The effects had even transcended the physical, leaving the once-proud Robert as a shadow of his former self, powerless to do anything but lie about the labs, all but paralysed by his condition.

In short, she was out of ideas. After exhausting every potential plan in her arsenal, there was really nothing else that Rosalind could do but wait. She still tried to care for him in between her usual work – the flow of progress, and the demands of Comstock, would wait for no man – but all she could do was wait and see if any opportunities or ideas to help him presented themselves in the meantime.

And so, for almost a week now, she had worked impatiently, watching over her brother with a practiced eye. This waiting for a solution to arise was frustrating, and she had never been good at sitting around hoping that a solution would crop up. Was it her fault that every time she tried something that she was sure would work, it inevitably and unceremoniously failed, leaving her back at square one?

Really, she was lucky that her experimental approach to finding a cure hadn't seemed to make him worse. She was a physicist, not a doctor. This wasn't exactly her usual field of expertise. Nor, to be fair, was it anyone's – Robert's case was rather unique, making it all the more difficult to help him. Still, she found herself stuck, at a loss for ideas that she could try or things she could do to bring back the Robert that she had first met, that long-ago day.

"It's getting dark," she said in an attempt to distract herself from that morose train of thought, her voice sounding unnaturally loud in the silent laboratory. "I should probably leave these papers for tomorrow. Before I fall asleep on them, that is."

Since Robert crossed into her reality, she had gotten in the habit of talking to herself. The sound of her voice seemed to soothe him sometimes; because it was familiar, she theorised. Besides, it sounded almost as though she was discussing things with him, as she had before. The fantasy was just that, a self-deception, but it was also comforting to her.

At this point, she had tried almost everything to bring him back to normal. Any small things she could do were a blessing, frankly. If she had to sacrifice a shred of decorum to help stabilise her brother, it was a sacrifice she'd willingly make.

With a grimace, she stood up from her desk, moving over to where her brother sat. She had made up a cot for him in the corner of the lab, with a chair and desk beside in case he felt like getting up. Right now, he was sitting on the edge of the bed in his slightly bloodstained shirt and trousers, one hand clamped over his constantly-bleeding nose and a vacant look on his face. As she approached him, he didn't react, instead staring through her vacantly as he always seemed to do.

"You must get better soon, brother," she murmured, looking down at her brother with a mournful glance. "You're not the man I know any more."

As she spoke, something in his blank expression shifted as he turned his head to face her properly. He still didn't speak. Instead, he simply blinked slowly at her, as though he was trying to remember something important.

It was at times like this that she could see the real Robert, struggling to clear the fog in his mind that was rendering him immobile. The Robert she knew was loud and expressive, always the first to laugh at a joke or come up with some insane theory that would somehow end up working. He was colourful and eccentric, the light of every room he stepped into, and about as much of a brilliant mind as she was. He was her brother. To see him like this – hunched over in his seat, skin pale and pasty, not having spoken in weeks, let alone even smiled at her – was almost breaking her heart.

Anxiously, she rubbed the nape of her neck with a weary sigh. There was no point in trying to get through to him. He was a ghost of his former self, unable to even respond to her simple enquiries about how he felt. Rationally, she knew that. Still, there was a small, hidden part of her that whispered 'maybe'. Maybe this time, he would reply. Maybe this time, he would look at her properly. Maybe he could be Robert again, rather than this familiar stranger she had found herself living with.

It was a nice fantasy. Not one she could believe in.

She stood with a yawn. Outside, the endless sky was a deep blue, the full moon large and bright, casting a white beam into the room even in the dim light of her desk candle. It was later than she had intended to stay up, but she was in the middle of drafting a new book, and had a tendency to get carried away when she was working on it.

Bidding Robert a muted goodnight, Rosalind was about to make her way upstairs, when out of the corner of her eye she noticed something. It was just another bit of furniture; something that had always been there and was as a result largely inconsequential. But seeing it sparked a memory. And that memory, rose-tinted and fringed with nostalgia, was looking oddly useful at this point. Almost as if, buried deep in her subconscious, the solution to Robert's problem was locked away, hidden until she could properly make use of it, and all she would need to do to unlock it was remember just what exactly had triggered this curious feeling.

That was when the idea struck her.

Slowly, she moved back to the wall, where a dusty brown piano was still wedged up next to small bookcase. Her lab was filled with such clutter, things she hardly ever used and barely even remembered about, but somehow she thought that this one might just have the answer.

The piano was a relic of the building's original purpose. At first, it was set to be a home, for the elite of Columbia to live in. Rosalind, however, had considered the large living space far too extravagant for her purposes, and had pulled out most of the furniture on the ground floor to make room for her equipment, essentially converting it into a makeshift lab.

However, time was precious. Research still needed to be done, and she didn't especially want to spend another day dragging the furnishings around when she could be doing actual work. As a result, some of the heavier things remained in the lab, shoved against the walls so they wouldn't take up too much space.

She had to admit, however, her reasons for keeping the instrument had a certain touch of the sentimental, beyond her practical necessities. Her half-remembered days of being instructed by her mother, small fingers expertly playing scale after scale, had left a larger imprint on her than she would have liked. It was her mother's first attempts to raise a more ladylike, 'respectable' daughter. Needless to say, it didn't work.

But while the lessons were mostly a waste of time, she had to admit a certain enjoyment in the activity. Music was a refuge from the bustling hive of her thoughts, washing over her and soothing her mind whenever a particular problem was threatening her very sanity. It had proven, somehow, to be a release over the years, a way to calm the stormy ocean of her mind, and one she often found herself turning to if ever she needed it.

Perhaps her brother would find the same comforts in its melancholic songs. She knew that he wouldn't share her nostalgia towards the instrument – at times, their childhoods were markedly different, and she doubted that he had ever been pushed to act like a 'lady' – but maybe the sound would soothe him as he sat.

If nothing else, the music could help him to sleep, lulling him into the sweet calm of his dreams. If nothing else, she could take comfort in that, and in the knowledge that she hadn't given up, that she was still trying to help him.

Sitting down at the piano, Rosalind began to play.

It was a piece she had learned when she was very young – one of the first that she could play be heart, in fact. The song had fast become one of her favourites, despite the fact that her mother hated it. It was almost a compromise between them; she finally engaged in a 'suitable' activity, and got to irritate her mother in the process.

Still, despite her earlier, childish usage of it, the song was a calming one. As the tune flowed from under her fingers, she closed her eyes, feeling the coolness of the key, their slight resistance to her gentle playing. It had been a long time since she had allowed herself this particular indulgence, and she had almost forgotten how peaceful it was.

She had been so busy of late, working night and day both to satisfy Comstock's demands and perfect the Lutece Tear or, later, to research some sort of solution to Robert's problem. So much so that she had almost forgotten what it felt like to relax.

The song washed over her, clearing her mind of thoughts and stresses. Soon, the music was all that filled her mind, snaking into her thoughts and permeating her brain. Her shoulders relaxed, and she leaned further forwards towards the piano, concentrating as hard as she could on the beauty of the music.

As she played, she hummed, a wordless tune that slid up and down with every change in pitch, her soft voice perfectly matching the old piano's oaky tones. Unbidden, a small smile appeared on her lips. Yes, this was exactly what she had needed.

Admittedly, it had been a while since she had last sat down at a piano, but she soon picked it up again, the tune becoming stronger, louder as her confidence grew. The sound filled the room, spilling out of the open window and onto the silent street. Smile growing, she leaned back, fingers dancing across the keys almost automatically. And as the music played on, she slipped further into her memories.

She remembered sitting next to her mother, hearing the music wash over her for the first time. Remembered meeting Robert, the way he talked so inspirationally about physics, the gleam of his smile and softness in his eyes. Remembered their determination to bridge the gap between their realities, working tirelessly to make their dream come true. A small chuckle escaped her lips as she fell further into her memories, into the soft sounds of the piano, into the warm glow of nostalgia.

She was so lost in her thoughts that she almost didn't hear Robert joining her.

His voice was low and harsh, unnaturally croaky from the time he had spent bedridden and unable to even address her. Nevertheless, he hummed along with her, his faint tones effortlessly harmonising with her own as she played on into the night.

Behind her, her brother had opened his eyes. They were as vacant and bloodshot as usual, but a peaceful smile was now adorning his face, giving him a calmer demeanour. For the first time in weeks, he seemed to relax. His head bobbed slightly in time with the music, almost imperceptibly, as he lay listening to her playing.

They stayed like that for what seemed like an eternity, Rosalind sat at the piano, Robert lying on the bed. Yet although they were apart, their voices were together, entwined in a tender melody that united their very souls. Rosalind could feel the wetness of a single tear on her cheek. Robert was in there. He was there, and he could hear her. She was bringing him back. Somehow, that was enough.

There was a rational explanation for it, of course. Assuming the same laws of physics applied, music was a constant between their two realities, something that is guaranteed to be the same no matter where they found themselves. And yet, she couldn't help herself absorbing the sentiment of it. She had been waiting for this moment for so long. After all this time, she and her brother could be together. It was as close as she could get to complete happiness, and she resolved to savour the moment as long as it lasted.

Finally, the piece ended. Rosalind lifted her hands from the keys, suddenly self-conscious. Her last, quiet note faded away, dissolving gently into the gloom. Without the music, the room seemed darker somehow, more empty. She shivered despite herself, pulling her jacket tighter over her body.

"Rosalind?" Robert croaked, his voice breaking the sudden silence that had befallen the lab. It was the first word he had spoken since he crossed into this reality. Trying to contain an excited grin, Rosalind went to him, standing in front of his hunched form.

"Robert?" Her voice was almost a whisper. Robert hesitated, his hands unconsciously balling themselves into fists beside him. After a moment, he spoke, his expression as impassive as ever.

"Almost." He looked up at her, chalk-white face seeming even pastier in the pale moonlight. His eyes were had widened, and the twinkle that she remembered so well had returned. He smiled, the movement no more than a twitch of his cracked lips, but it was the most expressive she had seen him in months. "I don't think I'm there yet."

"You need to sleep," she said, resisting the urge to keep him talking. She wanted to sit with him all night, to coax the colour back into his cheeks, the voice onto his lips, the Robert she remembered back into this ghostly shell of a body. But the dark smudges under his eyes betrayed his lack of real sleep, and she knew she was selfish for wanting to keep him up.

He nodded, mute again, and turned over on the small cot. Rosalind's face fell. That spark was fast fading from his eyes. Robert was leaving, being once again replaced with the empty man that sat in his place.

But he had spoken to her. She had seen him smile, heard his voice. The blood that periodically flowed from his nose had stemmed. It was only a small victory, but it was a victory nonetheless.

And as she went upstairs to her bed, she found that she was smiling. Tomorrow, she would play again. Slowly but surely, Robert Lutece would come back to her. Of that, she was certain.