burden of proof (love by induction)

Harry Potter - J. K. Rowling
M/M
G
burden of proof (love by induction)
Summary
BASIC STEP:Regulus knows what he's meant to do. It's simple. Befriend his brother. Gain his trust. Find the missing line from The Proof. Sell him out in exchange for his own freedom.ASSUMPTION:Regulus can do this without giving in. Gain a glimpse into this life without wanting to live in this endless summer afternoon forever. See his brother without wanting him back. See his first love without falling in love all over again.INDUCTIVE STEP:The assumption is wrong. Regulus was never really that good at math.ORGrowing up, growing apart, and growing together by the French Riviera.

Chapter 1

Regulus doesn’t know a lot about homecomings. He still knows they shouldn’t feel like this. 

The issue is this - all those big novels had always billed the prodigal son returning home as some sort of momentous occasion, the point of inflection in the trajectory of an otherwise regular story. Even the original parable of the prodigal son had some dramatics. A scorned brother. A weeping father. There’s a reason the story of the wayward son is seared onto stained glass, homecoming etched in technicolour to be preserved forevermore.

In comparison, Regulus’ return to Eze feels unremarkable. There are no childhood French idioms coming back to him, all the inside jokes he had with the language still lost in translation, so close but barely out of reach. He doesn’t look at the winding, cobbled streets through the car window and feel some sense of kinship. There is no unfurling of his chest, no lost tension in his shoulders. Regulus sits in the backseat of the car, picking desperately at the fraying strings of the seat and feels emptiness seeping into his veins. There will be no ballads composed about this. No songs written. No stories told. 

The car slows to a stop as they approach their old villa. Grimmauld Place looks exactly the same as it did back then, like time has warped around it, everything changing except the villa which has gone ahead and carried on as it always has. It has stayed pristine. Elegant. Untouchable. Wrong. The cold, marble pillars glare at Regulus mockingly. The white paint drawn across the walls seems to sneer at him stiffly. And, most of all, the door sits there, immutable and steady, a long crack running down its length. A singular fissure in an otherwise unblemished mirage of perfection. Regulus looks at that crack and feels like he is twelve again. Like he is drowning.

“Don’t get too comfortable,” his mother says from the front seat, her voice clipped, “We won’t be here for long.” 

Trust his mother to read his discomfort as pleasure.

“Yes, maman .” 

His mother says nothing back. As expected. Regulus stares at the back of her head as she parks. Does she feel it too? The seawater filling her lungs with every breath? The salty air acidifying in her mouth, scalding every swallow? The acrid taste of coming back to their house and having it just be a house without the person that made it home? The back of her head offers no answers. He’s not going to ask her now. Not now when he’s so close to escaping from her clasps. Regulus will just have to settle for not knowing. 

The car stops moving. His mother turns back to look at him. 

“Look,” she says, her voice even, steady, “This is important.”

This, he knows. They wouldn’t be back here, back in this house haunted by ghosts of those living and dead, with bitter memories etched like church murals on the walls, if his mother could see any other way. 

“You don’t want to be here, I know,” she continues, “But I see no other choice. If he agrees, this can be quick.”

He. The heir. The firstborn son. The prodigy. The scion of Eze reduced to a measly pronoun, an unremarkable monosyllable. Regulus admires it, then, how his mother expertly navigates around the elephant in the room. How she reduces the living, festering wound that hangs between them to nothing. 

His mother clears her throat. Oh. It’s time for Regulus to speak. 

“I understand, maman,” he says, “He will agree.”

At least, Regulus hopes he will. He will if he knows what’s good for him. But Sirius has never been one to know how to leap out of danger, say yes to something only to keep peace. His brother has always been the fighter - one to take things head-on. He hopes the years that stretch between them have changed this, that Sirius will listen to his mother when she asks of him something so small, something so momentous. For Regulus’ sake, if not his.

Regulus’ eyes meet his mother’s through the rearview mirror and sees the hardness in his gray eyes reflected back in hers. He knows, instinctively, that she is hoping for the same thing. Hoping that this will be easy. He hopes God will answer at least one of their prayers. If Sirius agrees, it will make his escape all the more easier. If Walburga is happy, she won’t bother to look for him.

In one swift move, his mother leaves the car and Regulus follows. The sea-breeze hits him immediately, so different from the still Irvine air he’s become accustomed to. It kisses his skin, caressing it gently, tousling his dark hair, a doting parent reaching for its favorite son. He hates it. Regulus reminds himself that this is temporary. Sirius will agree to what their mother asks of him. Tomorrow, he will be gone. Soon, he will be somewhere else. Paris, at least for a while. Then, maybe somewhere else. Just not here. Just not with his mother. 

“I’ll leave you to the house, then,” his mother says.

Regulus looks to face her. Walburga Black has never been one for jokes. But, surely, she must be joking now.

“What?”

“Close your mouth,” she says, voice harsher, “and watch your tone. I want to leave as soon as possible. I’ll go see him now and we can leave tomorrow.” 

She can’t be serious. She can’t be leaving him to do this alone. Not when he looks at the pristine, pure white stairs and still sees broken bones and dark pools of blood. Not when he looks between the cold, marble pillars and sees his brother’s broken silhouette, hunched over in pain, pleading with him for help. Not when every room, every wall, every floor tile, every nook, every crevice, every drop of paint, every inch of this place is screaming Sirius’ name. 

Not when in every immaculately shined surface, he sees his brother’s face reflected back at him, frozen the way it was the day he left. Disappointed. Angry. Accusing. 

“Don’t look at me like that,” his mother hisses, “I’m not the reason we’re here.”

At that, Regulus’ thoughts freeze. This is another punishment, then. For not being able to finish The Proof. For not being good enough. For not being Sirius. 

Regulus schools his features into practiced impassiveness. Straightens his lips into a thin line, sets his shoulders back to stand straight. He looks at his mother. He can’t afford to anger her now. Not when he’s so close. So, he nods. He is put together as his mother gets into the car. He is put together as she starts the engine. Regulus is put together as his mother leaves him in the rubble of what was once their family, what he once thought was love. Regulus does what a Black must do - he bears his punishment with grace.

And it is with grace that he carefully approaches the door to his old house. The jagged line cutting through the door that, in some cruel, twisted play by Fate’s hand, they never could fix, still sits there. He doesn’t know why they didn’t just replace the door entirely. They certainly must have considered it. It was a clue to their ever-rotating cast of dinner guests, all important, all keen and observant, that something was deeply, deeply wrong with the Blacks. Something they couldn’t pretend they didn’t see, like the bruises on Sirius’ skin hidden behind thinly applied concealer or matching welts creeping through Regulus’s cufflinks. Something the tantalizing beauty of Grimmauld Place, of money, of power, couldn’t hide. Something sinister. 

That doesn’t matter now. Grimmauld Place sits abandoned but for the dozens of invisible maids fixing the rooms in its winding walls, sitting ducks in the palm of its clasped hands. And Regulus. Regulus who takes a deep breath and opens the cracked doors to step into the hallowed halls of his childhood. 

Everything is exactly the same. He blinks. The entry hall looks as it always has. The grand staircase remains erected primly in the centre of the room. On the left, the piano sits untouched, with pristine white keys shining in the morning sun. Around the room, tasteful heirlooms are artfully placed to catch one’s eye. A centuries-old grandfather clock on the wall, its ticking reverberating through the empty room. A tea set with the family insignia ingrained into its cold surface. Not a speck of dust anywhere, almost as if, in two years, nobody has ever left at all. 

And, here’s the thing, Regulus wants. It’s unbecoming of him, unbecoming of a Black, to want so badly to see that time has passed, that something in this place has changed,  to see any indication that he is not who he was back then. That he has changed. He has not. Sirius’s words ring back at him, drowned in the uncharacteristic howling of the rain that had poured, drenched, and drowned their house That Night. Regulus will always be a coward. Before a Black, before his mother’s son, before his own person, he will always be a coward.

A stupid coward, apparently, because he still looks around the house, hoping to see that something has changed. Nothing has. The stuffy portraits on the walls of his father, grandfather, and all the Blacks before them, are still there, boring as ever. His mother’s favourite teapot remains firmly set by her bedside table. His own room still has books littered through it, his worn, well-dog-eared, annotated copy of The Little Prince still lying on his bed. He doesn’t reach to touch it. The Regulus who wrote in that book is gone now. He hasn’t been alive, truly alive, since That Night. That Night when all the words and poetry and sentences that lived inside him were forced and bent into the shape of sigma signs and fractals.    

Still, it’s Sirius’ room that hits the hardest. Regulus knows, instinctively, that nobody has touched his room since That Night. It’s easy to notice when clothes are strewn haphazardly across the floor, tossed out from the closest, as if Sirius was in a rush. There are records stacked messily in two piles on his desk as if Sirius was weighing which ones to bring with him and which ones to leave. The smell of blood still lingers in the air, all these years later. Sirius’ room feels like a crime scene. In some ways, Regulus supposes it is. 

But that’s not what draws blows at Regulus’ chest. It’s the whiteboard in the corner. It’s still littered with Sirius’ messy scrawl, words and numbers overlapping over each other, as if arguing and fighting for space on the board, forming a messy, overwhelming mosaic. There’s not a single blank space present. Every inch of the whiteboard is weaved together in multicoloured inky tapestry to form what once held - perhaps still holds - the key to Regulus’ freedom. Even within the mess, Regulus still sees it. Still sees the hints of The Proof. 

Regulus knows it’s fruitless. That if anything on that whiteboard was useful, Walburga would have copied it verbatim, tied it to a chair like a prisoner, and forced Regulus to spend hours inside interrogating it to yield answers. It doesn’t make sense to scour the whiteboard now, finding hints of the last statement they’ve been missing. But Regulus has never been one for sense. It’s why he’s never been able to crack The Proof, why he’s never been as good at math. Impulsive as he was, as he is, making sense had always been Sirius’ job.

So he spends the first few hours of his homecoming the same way he spent all his time in California - looking at foreign symbols, loving them, and praying they would love him back. They never do. So, in some ways, between Eze and Irvine, the miles that stretch between them, the ocean and land that divides them, nothing has changed. He’s back home, back in the same town as Sirius for the first time in years. The star-crossed brothers united at last. He’s back in the house that still tastes like blood, and bile, and paper, and fire, and smoke. And nothing has changed. Nothing that matters, anyways. 

Absentmindedly, scanning through another one of Sirius’ long inductive statements, Regulus wonders if, in another world, it could all have been different. If in another world, where the Black name was enshrined in art, or poetry, or acting, or music, The Proof wouldn’t matter. He can’t picture it. Math has always been the Black way. Immutable and traditional. Stone-cold and rational. Ancient. Insurmountable. So much like their family that the story almost writes itself. He’s sure, almost, that in another world, The Proof would still exist. Maybe it wouldn’t be about complex numbers and calculus, about zeta-functions and the triviality of zeros. But it would most definitely be something else. In every universe, Sirius would derive The Proof. Sirius would come close to glory, to being the perfect son. Sirius would throw it all away and leave Regulus to pick up the pieces.   

Regulus who doesn’t feel time pass around him as he sits in his brother’s room. It’s like the primordial spirit of Eze itself has wrapped its favourite son in a cocoon, suffocating him, but sheltering him from the outside world until he can scarcely hear a sound. It’s why he doesn’t notice the telltale signs as it starts to get dark. He’s so lost in Sirius’ math, the jigsaw pieces of himself he left behind that he doesn’t notice that Walburga isn’t back yet. And Walburga Black is never late. Never. 

It’s only when successive sounds of crashing echo through the house that Regulus stirs. Something’s dropped. Many somethings. Possibly many somethings made of glass, somethings inextricably precious and pretentious. One object destroyed would be easy to dismiss. Regulus and Sirius had once decimated a small but exorbitantly expensive vase purely by accident. But so many of them at once, a cacophony of broken glass howling through their mausoleum of a house in shrieking unison, could only be intentional. And there was meant to be nobody in the house. Nobody unless…

Regulus tiptoes down the stairs slowly. He is careful. He is poised, he reminds himself. He is graceful. He does not flinch when he sees his mother in the sitting room.

She carefully cradles an old vase, intricately carved, petting it affectionately as if it were her own child. Her grey eyes fill with bottomless affection, overflowing with warmth. Her eyes look like Sirius’ eyes. For a second, Regulus’ mother looks just like her too-soft eldest son.

Then, in one swift stroke, she hurls the vase towards the ground. It breaks - the vase, the illusion.

Walburga Black does not look away as the vase erupts in a million pieces around her, centuries of history evaporating before her empty gaze. The shards are in a mess all over the floor. Some sharp pieces are lodged in her hair. She doesn’t notice. She simply picks up another vase, one strikingly similar to the one Regulus and Sirius broke as kids and does the same thing. Again. Again. Again. Again. 

The violence doesn’t surprise Regulus. He’s been that vase before. Multiple times. It’s the tenderness before that bothers him. How his mother loves so beautifully, with so much heart and warmth, only to destroy what she once cradled. Burn what she once caressed so gently. So lovingly.

Walburga only sees Regulus when she turns to find another vase. And when she does see him, she transforms. She straightens, the vacant emptiness vanishes from her eyes replaced with cold indifference. Her mouth tightens into a docile smile. Her hands are still by her sides. And, just like that,  Regulus is face to face with a different person. 

“You’re here,” she says, “Come to the dinner table. What are you looking over here for?”

She leads him to the dinner table, her skirts sashaying around her as she expertly navigates the shards on the floor. As they sit down to eat, his mother practically oozes indifference. If Regulus were to ask, and he knows not to, she would say nothing had happened. That he was imagining things. That he was overreacting.

That it was all in his head. 

But he knows what he saw. He can still see the shards on the floor. One is sticking out of Walburga’s bun. He remembers the image of her breaking that vase, over and over again. Walburga can no longer convince him, telling him he didn’t see what he did. But once, she could. Regulus wonders how many memories he’s lost that way, memories he’s rewritten in his head with her words. He wonders how much of himself he’s lost.

They eat in silence. Regulus eats quickly. She eats slowly. Regulus tries to finish off his plate. Walburga reaches for seconds. He looks at his food. She looks at him. She never looks at him. Not unless she needs him for something. Not unless something’s wrong. Not unless he’s done something wrong. Does she know? No, she can’t know. There’s no way.

“Regulus.”

He looks at her. Grey irises meet grey.

Maman.”

“How are you liking your meal?”

He doesn’t even know what the kitchen has made. The green slush in his plates tastes like nothing, smells like nothing and even looks like nothing. He’s eating it because he has to. So he can leave the dining table. Leave the tension that now permeates the air, pooling inside him with every breath. He’s sure his mother feels it too. But why is she asking him about the food? What does she want?

“It’s good, Maman .” 

Maybe it’s just small talk. Like at a dinner party. If the dinner party was your teenage son.

“Great to hear. Perhaps you should have invited Evan and Pandora.”

“We’re only here for one night, Maman,” Regulus replies. Why is she bringing up Evan and Pandora? He doesn’t want to see Evan and Pandora now. Not when the salt is still rubbing against his lungs, the friction now leaving scars so deep that it hurts to move. To speak. 

“Have they written to you? Surely, they would write to you.”

Letters. They’re getting to the topic of letters. Slowly, the salt migrates from Regulus’ lungs to his blood, mingling with plasma so that there’s brine coursing through his veins. The seawater is everywhere. A few more breaths. He just needs to stay afloat. A few more breaths and Regulus won’t drown.

“Perhaps you missed their letters. Do look through the mail, won’t you, Regulus?”

She places a stack of letters in front of him. For a second, nobody moves. Silence. Stalemate. Then, because she has to win, always has to win, she nudges the stack again. He gulps. Regulus looks at the first letter. He sees the writing on the envelope. FromAlphard Black. To: Regulus Black. He sees his name. The seawater overwhelms him. At the dining table, Regulus Black drowns. 

“Did you think I wouldn’t notice, Regulus?” 

Regulus looks up at her. Her eyes look warm. Her voice is sweet, saccharine. She raises a hand to cradle his cheek. Despite himself, like a drowning man gasping for air, Regulus leans into the touch.

“Did you think I wouldn’t notice if you tried to leave?” she whispers, caressing his cheek, almost fond, “If you tried to run to my brother? Regulus, I’ve known for months.”

Her voice is so warm. Like honey spread over the perfect summer day. Like the serendipity of the first snow captured into a sound. He wishes he could bottle this moment up and keep it somewhere safe. Somewhere nobody, not even his mother, could taint it.

“I don’t understand,” Regulus says, “If you’ve known for months, why bring it up now?”

“The situation has changed.”

“Because of Sirius?” Regulus asks, eyes widening in realization, “Did he say no?”

And that’s the wrong question to ask. Wrong. Wrong. Wrong. 

Because his mother’s caress changes and suddenly Regulus’ cheek is stinging and a red welt is forming where his mother’s hands were. There’s a deep gash sprouting crimson blood where her signet ring had cut across his skin. 

If Regulus were to ask, and he knows not to, his mother would say nothing happened. All she did was cradle his face like any good mother would. But Regulus knows better.

“ He is living with the Potters. He refused to see me. For any reason. Outright refused to open the door.”

For a second, Regulus admires his brother. It takes courage to refuse. Giving in to Walburga would guarantee him a lifetime of peace. But for Sirius, it had always been the principle of the thing. He wouldn’t give Walburga an inch, let alone a line. One line. They were missing one line from The Proof. One line which only Sirius understood. One line which Sirius had now refused to give up. One line for which Regulus would now bear the weight.

He didn’t understand. What did his Mother want from him?

“But , Maman,” said Regulus, careful, “I can’t do what Sirius did. We’ve tried.”

And they had. They’d spent two years doing nothing but trying. Walburga had spent the past two years playing Prometheus, throwing Regulus into the fire of the world of math, a world that was never meant to be his, and hoping he would mould himself, mould the clay of his mind until Sirius stood in his place. They’d been to many places - New York, Chennai, La Paz, London. Lastly, Irvine. And Regulus had tried. He had really tried. He’d tried to love the numbers and the fractals and all the different letters that came so, so, so close to being words. But he hadn’t been able to do it. He hadn’t been Sirius. He hadn’t been able to find that one line, that one missing line of The Proof.  And that one line made all the difference.

“I know,” his mother replied simply, “I don’t expect you to. Not anymore.”

If Regulus wasn’t already drowning, the water in his lungs numbing and dulling his senses, this would hurt. But she’s not saying anything Regulus doesn’t know, anything he hasn’t heard from himself a million times before. He doesn’t care anymore, he tells himself, ignoring the seawater pushes at his trachea. He just needs to leave, go to Paris with Alphard as he’d planned. Leave his mother. Leave his brother. Leave The Proof. Leave it all as a distant story, a life that once belonged to someone else. 

He swallows. He can’t have it all if he doesn’t know what game his mother is playing. So, he asks:

“Then what do you want from me?” 

At this, Walburga smiles. She never smiles - she’s beautiful. It’s terrifying.

“Get me the line,” his mother says, casually folding her napkin.

“What?” Regulus replies.

“Get me the line,” his mother looks at him, “One line and I’ll let you go. You can go to Alphard, to Paris, to whatever frivolous life you want to live. Get that one line from Sirius and I’ll take you to Paris myself.”

At this, the water in his lungs pauses. Stops for a second. Regulus prides himself on being a planner, of having the foresight to know better. But he didn’t see this coming. The seawater is at war with his lungs. His lungs want to breathe now - they suddenly have a reason to, one they’d never imagined would exist. 

It goes like this - Sirius will never give Regulus that line. If what Sirius feels for Walburga is pure loathing, what he feels for Regulus is undoubtedly something worse. Something that comes from loving another person so much that the love makes your bones shatter and your eyes bleed until every joint in your body is one that doesn’t remember being unbroken. Something that comes from watching that love wither and turn to ruin and fester inside you like a curse rotting you from the inside. If he doesn’t know anything, he knows this. His brother hates him. He may not always have, but he always will. His mother has assigned him a task that is practically impossible.

But still. There’s hope. A selfish What If. What If he can escape? If Regulus doesn’t leave soon, he knows his fate. He thinks of the broken vase on the floor, shattered into a million pieces. You can glue a vase back together again and again but after a certain point, it won’t stick anymore. It will just stay shattered. Stay broken. Regulus thinks of his mother’s hands, the bruise on his cheek that she will swear doesn’t exist. If Regulus doesn’t leave soon, and get to Paris, there’ll be more bruises. More. More. More. Until there isn’t much of him left to bruise. He knows this - it has already begun.

Later, Regulus will look back and wonder what led him to agree so easily. Maybe it was a sickening sense of self-preservation. Maybe it was impulsiveness. Maybe some part of him just wanted to see Sirius again. Either way, on that dining table, on a swelteringly hot summer night, Regulus makes a choice. 

He says yes.