"Sirius." Cold, uncaring. As though he were addressing a stranger. The voice was a lie, though. He hoped Sirius could see it, although doubtless his brother's prejudices would blur his vision. Sirius only ever saw what he expected to. That was his greatest weakness; he believed the world was black and white. In his universe, everyone was either good or evi. There was no in between and he believed almost every single person wore their hearts on their sleeves.

Regulus hoped that his dear brother learnt his lessons quickly; he wouldn't survive very long in this world if he insisted on holding onto such naïve notions.

"Regulus." If his own tone had been cold, then Sirius' words had frozen to death before they'd even passed over his lips. There was so much hatred in his voice (not undeserved, though it hurt Regulus to hear it), and it gave Regulus the urge to get on his knees, to grovel and beg his brother's forgiveness.

He couldn't, though. Not yet. Not here.

"I need a word in private," he murmured, almost too low for passers-by to hear. Almost. "I have a room upstairs. If we could…?"

He left the last part of his question unasked, and Sirius frowned. "What? Follow you upstairs so you can dispose of me without causing a scene? I don't think so."

"Look," Regulus said, pulling out his wand. He should have expected this mistrust – he had expected the mistrust. Of course he'd known Sirius would hate and despise him. He was a Death Eater. But it still hurt.

At Regulus' sharp movement, Sirius' hand had flown towards his own wand, but when he saw that Regulus was holding it by its tip and not the handle, he relaxed slightly. He didn't, however, let go of his own wand.

"Take it," Regulus said impatiently, offering it to his brother. "So you know you can trust me. It's not safe to talk down here."

Sirius hesitated, and then grasped the wand. "Fine," he growled. "Lead the way."

Regulus nodded at the barkeep as he passed, and the man watched him silently, never ceasing the circular motions of his cloth on the bar. He wouldn't squeal; Regulus felt sure of that. All the same, maybe it would be prudent to wipe his memory after this was over. Just in case.

He led Sirius up a short flight of stairs and along a corridor, until they came to the room that he'd paid for. He pushed open the door and walked through, waiting for Sirius to follow. The other man did so warily, and never removed the tips of his fingers from the handle of his wand. After he'd come through, Regulus closed the door quietly and turned back to Sirius, who was looking around the room with a certain air of disinterest.

It was tidy and impersonal; there was a small overnight bag on the bedside table, but that was the only sign that anyone had been staying there. The other contents of the room all belonged to the pub; a worn-out table, a wooden wardrobe that had seen better days, a tidy desk (for if the purchaser of the room wished to attend to his correspondence), and a small single bed, pushed tightly into a corner and made with hospital-like rigour.

The decoration was no less plain; dingy blue walls with peeling paint and a ceiling that had become more grey than white over the years. Wood framed a window that looked out into a street below; the only thing that might pass for decoration in this plain room, seeing as there were no pictures on the walls. The scenery outside the window, however, was almost as grey and lifeless as the room; stone cobbles, unfriendly houses, and an overcast sky. The one sign of life was a gnarled old oak that stood on the footpath. Even then, its young green leaves were mixed with crinkled, dying ones of red and brown, despite the fact it was barely the end of summer. It was all hunched over, and Sirius thought it looked like on old man clutching his cane, still convinced that he was alive long after he'd died inside.

"It's been a long time, brother," Regulus said, after it became apparent that Sirius was not going to turn away from the window.

"I'm not your brother," Sirius said, his voice low. "We haven't been brothers for some time."

"We're related by blood, whether you like it or not."

Sirius let out a harsh laugh. "That's funny. Isn't it usually your lot who claim that family ties can be severed as easily as blasting someone's picture off a wall?"

"Sirius…"

"Don't. Just don't."

"Alright."

There was silence between them once more. "Did you kill them?" Sirius asked suddenly, after a few moments of this.

"Did I kill who?"

"Where do I start? The Prewetts?"

"No."

"Dearborn?"

"No."

"Benjy Fenwick?"

"No."

"Tarbeck Figg?"

"No."

"Marlene McKinnon? Tommy Camden? Roger Prince?"

"None of them."

"You seem awfully sure of yourself."

"I've never killed any Order members," Regulus replied steadily.

Sirius gave that humourless laugh once more. "Just helpless muggles and unsuspecting muggleborns who couldn't fight back then, was it?"

"Sirius…"

"No!" Sirius shouted, and the rage that was always so close to the surface these days suddenly shone through. "Don't 'Sirius' me, like you did when we were little! Don't think that you can call me here like our blood means something to me, or that our childhood counts for anything, because it doesn't! I should blow you to pieces, right now. I could, couldn't I? I have both our wands. It would be one less Death Eater for us to fight. Maybe hundreds less muggles will be murdered." He pulled out his wand, breathing heavily, and pointed it right between Regulus' eyes. "Tell me why I shouldn't," he said softly. "Give me one, good reason."

If Regulus had replied with 'Because I'm your brother', Sirius probably would have killed him. At the very least, he'd have incapacitated him and dumped him at Headquarters for the Order to deal with. But Regulus knew this; he knew his brother better than anyone else in the world did.

"Because I need your help," he said levelly.

And with those words, the fight drained out of Sirius. He lowered his wand, slowly, and for the first time, Regulus could see the toll the war had taken on his brother. He looked like the tree outside with its premature red and brown leaves. He lookedold.

"And you couldn't have come to me earlier," Sirius said bitterly. His voice was dead, and the words were almost a question. A question that didn't need answering. "I might have been able to save you, Reg." It was the first time he'd used Regulus' shortened name – the nickname he'd used when they were kids.

Suddenly, he lurched forwards and grabbed Regulus' arm. The other man almost jerked out of Sirius' grasp, but resisted the impulse. Sirius pulled up his brother's sleeve to reveal the mark tattooed on his skin. It was a dark and angry black, and Sirius winced at the sight. "I can't save you," he whispered. "Not anymore."

Now Regulus did pull away. "I don't need saving," he said harshly, pulling his sleeve down to cover it. "I know I'm past that. I'm as good as dead; I'm living on borrowed time; I signed my own death warrant. I don't need you to tell me all that. I know what I've done."

Sirius looked at his younger brother and, in that instant, Reg was a six year old boy again, scuffing his foot and unable to meet his older brother's eye because he'd done something wrong. And Sirius wanted to do what he'd done when they were children; he wanted to wrap his arms around Reg and tell him everything would be okay. He wanted to protect him from the world, because that was what older brothers did.

Some older brother he was.

"Then why am I here, Reg?" Sirius asked, falling heavily back onto the bed. "What do you need from me?"

"I need…" Regulus started to say, and then stopped. "I want your forgiveness. I don't deserve it, I know, but I… I needed to ask."

And then Sirius did step forward, and he did wrap his arms around his younger brother. "You'll have it," he whispered. "Always. For as long as I can give it to you."

Giving away forgiveness came with a cost.

"You can't say anything to anyone," Regulus told him forcefully. "Not even once I'm gone. Not even once everyone's gone. No one must ever know."

"Alright, alright," Sirius said. "Geez, calm down."

"No," Regulus said. "You can't ever tell. You have to act as though I was a Death Eater the whole time and then chickened out when they asked me to do something I couldn't handle, and you have to pretend that you still hate me. Always. Until we're both beyond Death's reach."

"Alright," Sirius said impatiently.

"Swear it," Regulus said. "Unbreakable vow."

And so Sirius swore it.

"Why is this so important?" he asked afterwards. "All this secrecy?"

"I'm not going to just lie down and die," Regulus said defiantly. "I need to… I think I can do a lot of damage. I know stuff that I shouldn't; stuff that's important. But no one can ever know that I know this information, elsewise they'll be a target."

"What sort of damage?" Sirius asked curiously. "What information?"

But Regulus shook his head. "I can't tell you," he told his brother. "I don't want to be the cause of your death."

"You can't make me a bigger target than I already am," Sirius said with a proud smile.

Regulus didn't smile back. "I wish that were true," he replied gravely.

When they parted, Regulus wrapped his arms around Sirius in a last brotherly embrace. Sirius let the warmth of his little brother wash over him, wishing he never had to let go. It was unfair that the thing he'd wanted most in the world, his brother's return to him, should come at such a high price.

"I wish there was another way," Sirius said as they let go of each other.

"There is," Regulus said with a sad smile. "I could obey and pretend to be submissive to the Death Eaters and live for much longer. But we both know this way's better." He walked towards the door, but turned around at the last moment. "You know," he said to his brother as an afterthought, "the Sorting Hat was going to place me in Gryffindor, but I begged it not to. I was too afraid of our parents. I wasn't brave enough."

"The Sorting Hat's never wrong," Sirius said. His voice was choked. "You're more Gryffindor than I am."

"I couldn't choose the right side, though."

"You did in the end."

"And look what it's cost me." He looked thoughtful for a moment. "It's worth it though."

Then he was gone.

Summer passed slowly and merged into autumn, with no news on Regulus reaching Sirius' ears. Every time he saw a tree shedding leaves, he was reminded of that dreary afternoon in the room above the pub, with the window looking out onto the tree that couldn't decide whether to be green, or orange, red and brown. And every time he remembered, he crossed his fingers and hoped for his brother's safety. And if he couldn't have that, then Sirius hoped he got a quick and painless death.

He saw the news before he heard it, written all over Remus and James' faces when he popped in one night. They looked sombre and reluctant – like the three of them had when they'd found Peter's guinea pig dead in its cage and they'd had to break the news to their twelve year old friend.

"What is it?" he'd asked, already knowing the answer.

"I'm sorry," Remus said, after he'd finished telling Sirius what'd happened. "I know your relationship was strained, but he was still your brother."

"Strained," Sirius laughed, a laugh that was a note too high and far too strangled to be normal. "That's putting it lightly." He had to turn away from his friends – their understanding looks were just too much. "He was a Death Eater," he continued. "Regulus was no brother of mine."

The words didn't choke him like he thought they would, but he had the horrible urge to rush upstairs to James' bathroom and swallow an entire bar of soap. "He died like a hero," he wanted to tell his friends. But he couldn't say the words. He'd promised.

He made his excuses and left, not missing the look that shot between James and Remus. Let them think he was mourning for the little boy Regulus had been once. They'd never know the truth; they'd never know of the man Regulus had grown to become.

But Sirius would. He'd know that his brother died on the right side.

There was no grave – or, at least, not one that Sirius knew of. He couldn't have risked being seen there, even if there had been one. But on his next day off, he apparated to the stream he and Regulus had played in as a child when their parents had taken them on picnics. He remembered learning to swim, there. He remembered teaching Regulus to swim.

He wandered down by the water and spotted the rock his brother had knocked himself out on, once. Well, if Sirius was honest with himself, they'd both played an equal part in that incident.

Regulus had been the one with the concussion, though.

His eyes fell upon a tall tree they'd clambered up when they were younger and nimbler. And much, much more innocent. It had been their dragon, Sirius remembered, and they'd been dragon tamers. It was covered in autumn leaves now – if you squinted, the masses of red could be the dragon's flames.

The tears came unbidden to his cheeks as he approached the old tree, and they left salty tracks as they rolled down his cheeks. How many memories had this tree seen; memories just like those moments of Sirius' and Regulus' childhood? Were they all gone now, like Regulus was?

He raised his wand and flicked it eloquently, slowly forming words in the air. When he stepped back, he admired the cursive writing that his magic had gouged deep into the wood. 'That'll never fade,' he thought to himself. 'Just like I'll never forget.'

Then he plucked a brown, dying leaf from a low hanging branch and slipped it into his pocket. The leaf would crumple and tear in time, but that was alright. Things tended to do that, as the years passed and the world kept turning. It was in their nature.

He cast one last cursory glance over the words in the tree before apparating away.

Mischief Managed, Little Brother.