Code Black

Regulus Black woke up to the sound of a shrill alarm, a groan escaping his lips as he fumbled to shut it off. His head pounded slightly, and as he turned over, he realized he wasn’t alone in bed. A muscular arm was draped over his waist, and a warm body pressed against his back. Slowly, hazy memories of the night before flooded in—drinks, laughter, stolen glances across the bar, the heat of whispered words against his skin, and then... this.

His stomach twisted uncomfortably. He was not the type to have reckless one-night stands. He was careful, calculated. He planned things out meticulously, made sure every decision was well thought through. And yet, here he was, in a stranger’s bed, his clothes scattered haphazardly across the floor. What the hell had he been thinking? He wasn’t thinking. That was the problem.

He twisted carefully to get a look at the man beside him. Tousled dark hair, sharp jawline, and an infuriatingly perfect smirk even in sleep. Of course, the universe would have him fall into bed with someone like this.

The man stirred, his eyes fluttering open, a lazy grin spreading across his face as if waking up beside a near-stranger was a perfectly normal occurrence. "Morning, gorgeous."

Regulus shot up, scrambling for his clothes. "No, no, no. This can’t be happening."

His mind raced. He needed to get out of here before this situation spiraled further out of control. There was no way this could end well. He yanked his trousers on, fingers fumbling with the buttons.

The older guy propped himself up on his elbow, watching in amusement as Regulus hurriedly buttoned his shirt. "You’re acting like you regret it. Didn’t seem like it last night."

Regulus huffed, running a hand through his messy hair. "I don’t even know your name."

His grin widened, all cocky confidence. "James. James Potter."

Regulus froze, his breath catching in his throat. No. No, no, no. The name was too familiar. A sinking dread settled in his stomach. "As in, Healer James Potter? One of the top mind healers at St. Mungo’s?"

James’s eyebrows lifted. "Guilty as charged. And you are...?"

Regulus groaned, feeling the blood drain from his face. "Regulus Black. First-year Healer-in-Training."

James let out a low whistle, clearly entertained. "Well, that’s an interesting twist."

Regulus didn’t wait to hear more. He grabbed his bag and bolted, his pulse hammering in his ears. The sheer magnitude of his mistake weighed down on him. He had to hope—pray—that he wouldn’t run into James at the hospital.

But fate, as always, had other plans.

The halls of St. Mungo’s buzzed with the usual chaos as Regulus tried to focus on the tour his supervising Healer, Minerva McGonagall, was leading. Alongside him were the other trainees: Barty Crouch Jr., Dorcas Meadows, Evan Rosier, and Pandora Rosier. Each of them carried varying degrees of excitement and nerves, though Regulus felt nothing but dread.

How had he gotten himself into this situation? A one-night stand with a senior healer? That was the kind of reckless, idiotic behavior he had spent years avoiding. His entire life had been about control, about making the right decisions. And yet, here he was, caught in the worst possible position before his training had even properly begun.

McGonagall led them through the various wards, explaining their responsibilities and expectations, but her words barely registered in his mind. Then suddenly, her voice cut through his thoughts.

"And this is where you’ll be shadowing one of our senior Healers. Ah, here he is now. Healer Potter, meet your new trainees."

Regulus turned, and his stomach dropped.

James stood there, looking entirely too pleased with himself, his smirk even more unbearable in the bright hospital light. He looked perfectly at ease, arms crossed over his chest as if this were all some elaborate joke. How was he so unbothered by this? Did he just... not care? Meanwhile, Regulus was actively considering throwing himself out of the nearest window.

A familiar presence caught at the corner of his vision, stiff and unmoving. Regulus knew who it was before he even turned.

Sirius Black stood beside James, arms folded over his chest, clad in Healer’s robes that looked strangely fitting on him. It was an odd sight—his brother, once the reckless, rebellious son who had fled their family, now grounded in this profession of healing and responsibility.

Regulus felt his pulse quicken, but he kept his face carefully blank, his posture rigid. He did not turn toward Sirius, did not acknowledge him, even as an unspoken tension settled thick in the air.

Their last encounter had been years ago, a bitter shouting match at Grimmauld Place that had ended with Sirius storming out and never coming back. Regulus had been left behind, left to navigate the maze of their parents’ expectations alone. He had always wondered, in the quiet, sleepless nights, if Sirius had thought of him at all since then. If he had felt the same loss Regulus had, the same lingering ache that never quite faded.

Now, standing mere feet apart, it was as if none of it had ever happened. Sirius said nothing. Regulus said nothing. The space between them was filled only with silence—heavy, suffocating, but unbreakable.

McGonagall continued speaking, her voice distant in Regulus’s ears. The moment passed, and the tour moved forward. Regulus followed, his face impassive, his steps measured. He did not look back.

Later that day, during a rare break, Regulus found himself in the trainee lounge with Barty, Dorcas, Evan, and Pandora.

Barty was the first to speak, leaning back in his chair with an exasperated sigh. "Well, that was... an experience. I don’t think McGonagall even stopped to breathe through that entire tour."

Dorcas smirked, stretching her arms above her head. "Welcome to St. Mungo’s, where the first rule is to always keep up, and the second rule is to never ask stupid questions."

Evan chuckled, running a hand through his hair. "Not that it stopped Pandora from asking about every single thing we walked past."

Pandora shrugged, entirely unapologetic. "I like to know what I’m walking into. If that means asking about the probability of being attacked by a cursed artifact on our first week, so be it."

Regulus listened, remaining quiet as the others continued exchanging first impressions. He knew he should contribute, but the weight of the morning still pressed against him. James Potter. Sirius Black. Both of them inescapable, both of them far too close for comfort.

Barty’s eyes flicked to him, sharp and knowing. "You’ve been quiet, Black. Something on your mind?"

Regulus hesitated, then shook his head. "Just... processing the day so far."

Dorcas snorted. "I think we all are. Surviving McGonagall’s orientation is a rite of passage."

Pandora nudged him playfully. "Don’t worry, Regulus. We’ll survive this together."

He managed a small smile, though his mind was still elsewhere. He wasn’t entirely sure survival was guaranteed.

Regulus barely had time to breathe before they were thrown into the chaos of their first real shift. No sooner had the trainees been introduced to their respective mentors than a flurry of Mediwitches and Healers came rushing through the hall, pushing a floating stretcher. A young wizard, barely in his twenties, lay unconscious, his entire body seized in a violent magical convulsion.

McGonagall’s voice rang out sharply. “Cursed wound, third floor. Rosier, Meadows, with me. Crouch, Black, Lovegood, you’re with Healer Potter.”

Regulus barely had time to react before James was already striding forward, all charm replaced by crisp efficiency. “You heard her—move!”

Regulus followed, dodging past bustling Healers and levitating parchment files. They burst into a treatment room just as the patient let out a strangled gasp, his body arching off the stretcher, his limbs shaking uncontrollably. Dark tendrils of cursed magic crawled up his arm, blackening his veins.

“Bitten by an unclassified magical creature,” one of the Mediwitches reported breathlessly. “Some kind of venom—his heart rate is through the roof.”

Regulus swallowed hard, his pulse hammering. This was no training scenario.

James didn’t hesitate, flicking his wand to scan the patient. “Crouch, blood stabilizing charm. Lovegood, get me a vile of Mandrake Draught and a bezoar. Black—”

Regulus straightened, waiting for an order.

James turned to him, eyes sharp. “You’re with me. We need to identify that venom before it spreads to his lungs.”

Regulus hesitated only a second before stepping closer, trying to focus. The magic surrounding the wound pulsed and shifted. It wasn’t just a simple bite—it was evolving.

Regulus’s mind raced. Think, think. What could do this? His fingers twitched as he reached for his wand. A diagnostic spell flickered in the air, revealing something strange. The venom wasn’t from just one creature—it was mixed.

His breath caught. “It’s a hybrid venom.”

James glanced at him, expression sharpening. “Explain.”

Regulus exhaled. “Multiple magical properties, layered together. It’s shifting, adapting to counter our healing magic. If we use a standard antidote, it’ll mutate again.”

For a brief second, something flickered across James’s face—something like impressed curiosity. “Smart,” he muttered, before turning to Crouch. “Forget the Mandrake Draught. We need a neutralizing agent that can adapt alongside the venom.”

Crouch frowned. “Like what?”

James turned back to Regulus. “What’s your solution, Black?”

Regulus’s throat went dry. The weight of expectation pressed down on him. James was testing him. And more than that—he trusted him to have an answer.

Regulus’s mind spun through every textbook, every obscure potion he had studied. Then it hit him. “Ashwinder egg essence.”

James grinned. “Brilliant. That’ll counter the magical instability without fighting the healing process.”

He turned to a Mediwitch. “Get me a vial. Now.”

Within minutes, the antidote was administered, the dark magic fading as the convulsions slowed. The patient’s breathing evened out, his body going limp as unconsciousness took over. The danger had passed.

The room exhaled.

Regulus felt the tension seep from his muscles as he stepped back, heart still racing. He had done it. He had kept up.

James clapped him on the shoulder, his touch warm and solid. “Not bad, Black. Not bad at all.”

Regulus stiffened but didn’t pull away fast enough to stop James from noticing. The knowing smirk was back.

“You’re going to be interesting to work with.”

Regulus barely had time to formulate a retort before James had already turned, calling for the next patient.

Regulus exhaled, running a hand through his hair. One shift in, and it was already a disaster.

And yet—his heart thrummed at the thought of what came next.

Hours later, the chaos of their first shift had finally settled, but the tension in Regulus’s chest had not. His mind still buzzed with the weight of the day—his mistake of last night, the unexpected encounter with Sirius, and James bloody Potter looming over everything like an unstoppable force.

Needing air, he slipped away from the trainee lounge and made his way up to the rooftop of St. Mungo’s. The night was cool, the London skyline stretching endlessly before him. He exhaled sharply, hands gripping the railing as he tried to process everything.

“You know, if you keep brooding like that, people might start to think you have feelings.”

Regulus tensed at the familiar voice, eyes shutting briefly before he turned. James stood near the rooftop entrance, hands shoved into the pockets of his healer’s robes, looking far too comfortable for someone who had just worked a grueling shift.

“What do you want, Potter?” Regulus muttered, looking away.

James stepped closer, tilting his head. “Figured I’d check on my favorite trainee. You looked like you were about to combust earlier.”

Regulus scoffed. “I’m fine.”

James hummed, unconvinced. “You’re a terrible liar.”

Regulus’s fingers tightened around the railing. “What do you want?”

James sighed, leaning against the railing beside him. For a moment, there was only silence, the distant hum of the city below. When James finally spoke, his voice was softer, lacking its usual teasing edge.

“You did well today.”

Regulus blinked, turning his head slightly. He expected sarcasm, another cocky remark—but James’s expression was unreadable, his gaze fixed on the skyline.

Regulus looked away. “I don’t need your validation.”

“Maybe not,” James said easily. “But you’ve got it anyway.”

Regulus swallowed. The words unsettled something deep inside him, something he wasn’t ready to name.

James shifted, glancing at him sideways. “And, for what it’s worth… Sirius was watching you today.”

Regulus’s body went rigid. “I don’t care.”

James let out a low chuckle. “Another lie. You really should work on those, Black.”

Regulus turned to glare at him, but James wasn’t smirking this time. His expression was unreadable, but his voice was quiet when he said, “He looked proud.”

Regulus’s breath caught.

He turned away sharply, his throat tight. He had spent years pretending his brother didn’t exist—pretending the ache of abandonment didn’t still sit heavy in his chest. To hear James say that, so casually, so easily—like it didn’t threaten to crack something in him—was unbearable.

James must have sensed the shift in his mood because his voice took on a lighter tone. “You can keep pretending you don’t care. But eventually, you’re going to have to face it.”

Regulus exhaled through his nose. “You sound like you enjoy making my life miserable.”

James grinned. “Oh, I do.”

Regulus turned, meeting James’s gaze head-on. The weight of the night, of the day, of everything between them, lingered in the space between their bodies. James was too close. Or maybe Regulus was.

James’s voice dropped, just slightly. “You running away this morning—was that about the job? Or was it about me?”

Regulus’s stomach twisted. He refused to answer. He refused to look at James.

A beat of silence.

Then James stepped back, as if sensing Regulus was at his limit. “See you tomorrow, Black.”

He turned and walked away, leaving Regulus alone with his thoughts, his regrets, and the undeniable fact that James Potter was going to be impossible to ignore.

Regulus moved through the hospital corridors with the sharp precision of someone who refused to be slowed down. The night shift was dragging, his limbs heavy with exhaustion, but he wouldn’t allow himself to falter. He had learned early that to show weakness was to invite disaster. It had been a lesson beaten into him—sometimes with words, sometimes with silence, sometimes with a withering look from his mother that cut deeper than any curse.

His last patient had been particularly difficult—a middle-aged wizard suffering from a lingering curse wound, too proud and stubborn to follow instructions properly. Regulus had spent nearly an hour trying to convince the man that ignoring treatment would only make things worse, but his patience was wearing thin. He wasn’t good at softness, at gentle coaxing the way others were. He was good at results. Efficiency. Getting the job done.

The moment he stepped out of the ward and into the quiet hallway, he exhaled, rolling the tension from his shoulders. He had a brief window before his next rounds. Maybe a few minutes of peace. Maybe he could—

“Black!”

Regulus’s breath caught, his entire body tensing before he even turned around. He knew that voice.

Sirius.

His pulse kicked up, but his expression remained blank as he slowly pivoted on his heel.

Sirius stood at the other end of the corridor, leaning against the wall with his arms crossed. He looked… the same, and yet entirely different. His hair was still wild, his stance still defiant, but something about him had changed. There was less recklessness, less of the sharp, rebellious edge that had always made him feel untouchable.

Regulus hated that he noticed.

He held his ground as Sirius took a few steps closer, closing the space between them.

“Didn’t think I’d see you here, little brother.”

Regulus swallowed down the instinctive flinch at the words. He hadn’t heard Sirius call him that in years, and it sat uncomfortably in his chest, like a blade pressed against old scar tissue.

He kept his voice steady. “And yet, here I am.”

Sirius let out a quiet huff of laughter, shaking his head as if he still couldn’t quite believe it. “Healing, of all things. Didn’t think that’s where you’d end up.”

Regulus’s jaw tightened. You didn’t think of me at all, did you?

He could still hear their mother’s voice in the back of his mind—You will not be like him, do you understand? You will be better. You will make us proud. The lessons had been drilled into him until he had no choice but to believe them. Sirius had been the failure, the lost cause, the one who had turned his back on the family name. Regulus had been the one meant to fix things, to prove their bloodline was still untarnished.

And yet, somehow, here they both stood—on the same side of a world neither of them had been raised to belong in.

“You don’t know anything about me,” Regulus said, his voice cool, controlled.

Something shifted in Sirius’s expression. He held Regulus’s gaze for a long moment, and for the first time, there was no challenge in his eyes. No defiance. Just something quieter. Something unreadable.

Then, finally, Sirius nodded. “Guess I don’t.”

Regulus expected to feel triumphant at that. Instead, all he felt was hollow.

Before he could figure out what to do with the uneasy feeling curling in his stomach, a second presence joined them.

James Potter.

Regulus bit back a groan. Because of course. Because this night isn’t miserable enough already.

James appeared at Sirius’s side, his usual confidence softened slightly as he glanced between them, clearly sensing the tension hanging thick in the air.

“Everything alright?” James asked, voice casual, but his eyes flickered with curiosity.

Sirius smirked, but it didn’t reach his eyes. “Peachy.”

Regulus clenched his fists at his sides. He had to get out of here. The weight of the past was pressing in too hard, the ghosts of his childhood clawing at the edges of his carefully built composure.

He didn’t respond. Didn’t give Sirius or James a second glance.

He just turned and walked away.

Regulus barely had a moment to breathe before the next emergency case was thrown at them—an experimental potion accident, a seventeen-year-old witch on the brink of magical and physical collapse. It was the kind of case that demanded everything he had left, which, at this point, wasn’t much.

He didn’t have time to process the unbearable presence of Sirius in the observation gallery, didn’t have time to linger on the way James Potter had spent the entire shift watching him like he was some sort of puzzle that needed solving. The world narrowed to the girl on the cot, her body seizing against the restraints as her magic flared uncontrolled. Her vitals were dropping too fast. The potion had done something to her core, was stripping away her stability, layer by layer.

Regulus fell into work without hesitation. Spell after spell, diagnostic after diagnostic. He heard James barking instructions at another healer, heard the frantic shuffle of feet and rustle of robes as mediwitches prepared for the worst. But Regulus barely needed words.

He was moving before James could instruct him, anticipating his next step like they had been doing this for years instead of hours. James had barely lifted an eyebrow before Regulus was pressing a restorative potion into his hand. Regulus glanced at the chart, and James was already shifting their approach.

It was infuriating, how easy it was to move with him. How right it felt.

And yet, Regulus didn’t have time to think about that, either.

The girl stabilized—miraculously, after what felt like an eternity—and the room exhaled as one. Someone clapped James on the back. Someone else muttered something about getting a report started. The air was heavy with relief, but it didn’t reach Regulus, not yet.

His pulse was still hammering. His muscles were still tight with the ghost of failure, of the thought that they could have lost her. And beneath it, tangled deep where he refused to acknowledge it, was something else.

Because they had worked well together. Better than well.

And that terrified him more than the idea of failing.

Regulus exhaled slowly, bracing himself against the nearest counter, trying to ignore the burn of exhaustion. His body was starting to catch up to the past twelve hours, weighing him down like lead. He had no energy left to deal with him.

But, of course, James Potter had no concept of timing.

“You survived your first shift,” James said, and he sounded far too pleased for someone who had just spent the entire night drenched in stress and blood.

Regulus scoffed, pushing back from the counter, fixing him with a deadpan stare. “Barely.”

James grinned, wiping his hands on his robes. “Not bad for a first-year. I’ve seen worse.”

Regulus’s exhaustion was suddenly eclipsed by irritation. “That is not reassuring, Potter.”

James only laughed, a deep, amused sound that grated against Regulus’s already frayed nerves. He wanted to snap at him, wanted to say something biting, but there was no energy left for arguments. No fight left in him. And that might have been the worst part—James Potter had drained him to the point where he didn’t even want to hate him properly.

He should hate him. Should resent the way he moved through the world so easily, should loathe the way he had settled into his life like it had always been his. James had everything Regulus had ever been told he couldn’t have—freedom, warmth, the luxury of belonging. It was maddening.

And yet, standing there, sweat-soaked and aching, Regulus felt something dangerous creeping beneath the surface.

Something like familiarity.

The hospital was finally quieting down, the last of the overnight chaos ebbing into a strange, liminal hush. The light had begun creeping in through the high windows, soft and golden, painting long shadows across the polished floors. For a second, Regulus let himself stand there in it, let himself feel the weight of the night settle over him.

And then—

“Trainee Black.”

Regulus straightened so fast it sent a fresh wave of pain through his shoulders. He turned to find McGonagall watching him with her signature unreadable expression.

“Yes, Healer McGonagall?”

She studied him for a moment, assessing. Then, she nodded. “Well done tonight.”

Regulus blinked.

Praise wasn’t something he was accustomed to. Not from people in authority, not from people who mattered. He could count on one hand the number of times someone had looked at him like he was capable, like he had done well. His parents had never bothered. No amount of perfection had ever been enough for them.

So he didn’t trust it.

Didn’t trust the way it sent a strange, unfamiliar warmth curling in his chest, didn’t trust the way his throat felt tight around the words thank you. He merely nodded, stiff and controlled, because he didn’t know how else to react.

McGonagall was gone before he could linger on it.

But James was still there.

Regulus turned, and James was watching him.

That was becoming a problem.

James had that look again—the one that made Regulus’s skin itch, like he saw something Regulus wasn’t ready to acknowledge. He had spent the entire night catching him off guard, unraveling him piece by piece, and Regulus hated it.

He should say something. Should tell him to stop staring. Should demand to know what he found so interesting.

But James only smirked.

“I’ll see you tonight,” he said casually, stretching, like they weren’t both on the verge of collapse.

Regulus frowned. “What?”

James shot him a look, equal parts amused and mocking. “We have another shift together, Black. Try to keep up.”

And just like that, he was gone, whistling under his breath as he disappeared down the corridor.

Regulus stood there for a long moment, silent, the hum of the hospital pressing in around him.

He had barely survived one night with James Potter.

And now, there would be countless more.

He exhaled sharply, dragging a hand down his face.

This was going to be a disaster.