The building was… nice. No place he would ever live, but then again, he and Sirius had always had different tastes.

No. That wasn't true, was it? Not always. When they were younger…

Not the time, Regulus.

He crossed the dark street, hood of his cloak pulled up to hide his face. Someone might be watching and everything – everything he'd discovered, all his stupid mistakes, and now this chance, this only chance, it would all be wasted if he wasn't careful.

It was late. Nearly three a.m. His stomach turned nervously, thinking about all the different reactions his brother might have. He shook his head and used his wand to open the lock on the front door before slipping into the building.

The flat was on the fourth floor.

All he had to do was explain himself. He would just tell Sirius; finally stop pretending that this was what he wanted.

He needed help. He needed help and had no one else to go to – no one else he could trust. Because Regulus knew, he was positive that if he told Sirius exactly what was happening, what he was planning to do, his brother would help him.

Because Regulus knew if the situation was reversed he would do the same.

He made it to the fourth floor.

405.

He hesitated only a moment before walking down the hallway and stopping in front of the door to his brother's flat. A breath, quick and deep, and then he knocked.

Several moments passed. Nothing.

He was home, he was home, he had to be home.

He knocked again, louder, a feeling of desperation creeping into his heart.

And then, after a few more agonizing moments the door finally opened.

His heart dropped into his stomach at the sight of a young tawny haired man standing in the doorway, wearing pajamas and looking like he'd been roused from sleep. Remus Lupin looked much the same as the last time Regulus had seen him, save for a few streaks of gray that now littered his hair.

Of course Sirius had shacked up with his boyfriend.

Regulus made quite a show in school about his dislike for Lupin. His blood, his poverty, his queerness, all of it was fair game because in Regulus's mind, it was Lupin's fault his brother had left. Sirius cared about Remus more than he'd cared about Regulus, and that hurt Regulus deeper than he'd ever admit. Sirius had walked out the door and left Regulus stuck in Grimmauld place, turned his back on his own brother, just for these friends.

Lupin's expression immediately turned wary at the sight of the hooded person, and Regulus almost thought that the man was an idiot, blindly opening his door at a time like this, when no one could be trusted. Then he saw the way Lupin had positioned himself, right arm at his side, the hand surely holding his wand hidden from view.

"Can I help you?" he asked.

Regulus said nothing for a long moment. He didn't have time to come back another day in the hopes that the next time it would be Sirius answering the door. Slowly, he reached up and pushed his hood back.

Lupin's expression slid from wary to surprised to cautious. Regulus was sure Sirius had told him he was a Death Eater. "Regulus?"

"I need to see my brother," Regulus said.

Lupin stared at him, trying, perhaps to uncover his motives. Regulus glanced away, uncomfortable with the scrutiny.

"I'm sorry," Lupin finally said. "He's not home."

Regulus's gaze snapped back to him. "When will he be back?" he asked, hating it when he realized how desperate he sounded.

Lupin seemed to realize it too, blinking at the unexpected tone. "I don't know…"

He needed him. He needed him. Why was he never there when he needed him?

"Where is he?" Regulus asked, swallowing hard against the panic he could feel growing.

"I don't know," Lupin repeated, and the earlier suspicion had all but vanished, replaced with something that might have been concern. He paused, seeming to consider for a moment before finally saying, "Would you like to come in and wait for him?"

And then, as if the universe was rubbing salt in the wound, Regulus felt his arm burn. He hissed and gripped at it tightly through his robes, though experience had taught him that nothing made the pain stop.

Terror seized him, then. Because he couldn't go back. Not with his plans. The Dark Lord would know. He'd read the thoughts from his mind as easily as if they were on paper. Tonight, he had to go tonight. Before He realized Regulus was missing and what he had done.

He took a few steps backward, nearly stumbling.

"I can't," he said, words coming out more choked than he intended.

Lupin definitely looked concerned then, stepping from his spot in the doorway and out into the hall. "Regulus, please, come inside. He should be home this morning at the latest.—"

He couldn't wait, he didn't have time. Tonight, it had to be tonight. Regulus shook his head and turned to flee back down the hall.

"Regulus, wait!" Lupin said, reaching out and grabbing hold of his wrist.

Regulus pulled his wand on instinct, spinning around and aiming it at his face, eyes wide and wild, with a touch of pure fear in them. "Let go of me," he said, breaths coming quickly as he tried to reign in his panic.

They stared at each other. Lupin didn't raise his own wand, which was in his other hand as Regulus had thought.

Lupin opened his mouth to say something, his grip on Regulus's wrist loosening, but Regulus was suddenly grabbed from behind, yanked back by the hood of his cloak and then thrown against the wall next to him. His back bounced off the wall and before he could react there was a hand around his throat and a wand pointed at his neck.

And there was Sirius, face dark with near rage. "What the fuck are you doing here?"

Regulus was vaguely aware of Lupin exclaiming, "Sirius!"

He couldn't answer his brother, however, because the hand around his throat was tightening, cutting off his air supply. He'd dropped his wand in the surprise, and so his hands went up to try and pry at Sirius's fingers, not having much success.

"What were you going to do to him? Huh?" Sirius demanded.

Regulus tried and failed to shake his head, still clawing at his hand, which was only gripping tighter.

Please, he thought. I need your help.

Sirius dug his wand into Regulus's neck. "I should kill you," he spat. "You deserve to rot."

And suddenly Regulus knew that Sirius wouldn't help him. And he did deserve that. He did. He'd done things he'd never atone for. Never. Sirius wouldn't help him, and Sirius shouldn't help him.

The edges of his vision started to go black and he heard, "Sirius, let him go! He came here for you – he's in trouble! I think he's in trouble—"

The grip loosened quite suddenly and he slid to the floor, coughing and gasping for air. He saw his wand next to him and grabbed it, scrambling to his feet, one hand on his neck as he wheezed. He realized his eyes were wet and wondered when that had happened.

Sirius was staring at him, expression hard, but slightly unsure. "Regul—"

"Goodbye, Sirius," he rasped. Sirius seemed to realize the finality behind the words and moved toward him, starting to say something, but Regulus apparated before he could hear what it was.