Just something I wrote in a few hours, between not doing work and not writing my chapter fics. One day I'll post updates, I promise! Hopefully before Deathly Hallows comes out, ok?

I think the relationship between Sirius Black and James Potter has always intrigued me more than any other friendship in the series. Possibly because they are my favourite characters (I haven't been a big Sirius fan of late, but I'm warming up to him again).

And ever since OOTP, that line in POA about them being 'almost brothers' has been running round in my head. After all, Sirius already has a brother, a real one.

I guess where I'm going with this is that, even though James and Sirius may seem like brothers, they're not. And even though Sirius left his family behind, there are times when blood is important.

And I love Regulus.

Plotbunnies ataaack!

Almost Brothers

December, 1979

'Sirius, mate – are you all right?'

Sirius looked up – for a moment James thought that his friend didn't even know who was speaking to him. Finally, after a few surreal seconds, his grey eyes seemed to focus.

'Hey, Prongs.'

James sat next to his best friend, worried. He'd never seen Sirius like this before. He was always so sure of himself, so confident – this defeated pose, those tired eyes; they weren't like the Sirius that James knew at all. In fact, had he not known Sirius as well as he did, he would have sworn that there remained the faint traces of uninterrupted tears on his face.

'Padfoot?' James said uncertainly, hoping the old nickname would cheer him up a little. 'What's wrong, mate?'

James noticed that Sirius' left hand shook – the piece of parchment he was holding only accentuated the movement. Noticing James' eyes on it, Sirius promptly crushed the paper into a ball.

'It's nothing,' he said. But James always knew when his friend was lying.

'Come on, Pads. It's not nothing.'

Sirius lobbed the parchment ball into a corner of the room.

'It's nothing,' he repeated, taking a deep breath and looking James squarely in the eye. 'We should get to work, shouldn't we?'

James frowned.

'Don't look at me like that, James,' Sirius muttered, looking away. 'We've got things to do – saving the world and all that – which are much more important than my mood swings. So just … don't look at me like that.'

'Sirius, I want to know. What's wrong?'

'It's not important, I'm telling you. We've got Death Eaters to sabotage, come on …'

He was getting to his feet, but James grabbed his shoulder and pulled him down.

'Sirius Black, if you don't tell me what it is, I swear I'll put Lily onto you,' James threatened. 'Forget about the mission for a second, will you? Tell me.'

'It's. Not. Important.' Sirius said again. But James shook his head.

'No, it is important, so stop acting like a git about it. If you can't tell me, who are you going to tell?'

Sirius glared at him. 'No one, preferably,' he said. And then, as though to emphasise his point, he got to his feet and headed for the door. James stood, thinking desperately how to call him back.

'Marauder's code!' he blurted out. Sirius stopped.

'What?' he demanded, a slightly disbelieving smile curving his lips as he turned.

'Marauder's code, rule two,' James said, with more conviction this time. 'No secrets-'

'-between marauders,' Sirius finished, raising an eyebrow. 'I remember, James.'

James nodded. 'That's right. So you have to tell me.'

'James, we were thirteen. You're not seriously going to hold me to-'

But James sent him a look which he knew would give his best friend all the answer he needed.

'I assume you remember the punishment for breaking the marauder's code, Padfoot?'

Sirius' expression blackened.

'You wouldn't,' he said, but James could tell that he didn't entirely believe it.

'Wouldn't I?'

Sirius sighed. 'Git,' he muttered, moving back to the couch and resuming his earlier dejected posture. James took the seat next to him again and waited.

Since it was James, though, he didn't wait particularly patiently.

'So?' he asked, after a minute's silence.

Sirius was very carefully avoiding his eyes.

'Regulus is dead.'

His voice was hollow as he said it. James, who had half been expecting his best friend to declare his undying love for some unattainable girl – just as James himself had done so many times during their schooldays – was momentarily blown away by the news. And he couldn't for a second begin to understand how Sirius could treat it with so little emotion.

'Not really nothing, then,' he said quietly. Sirius shrugged.

'I'm not sure. Idiot probably deserved all that he got.'

James winced.

'That's a bit harsh, Pads. He is your br-'

'He is not my brother,' Sirius said, suddenly angry. 'Not him. Look, James, I don't have time for this. Let's just go, shall we?' He got to his feet again.

But James was still hesitant.

'I don't think that's a good idea, Sirius. It could be dangerous out there. Shouldn't we talk about this first?'

'I don't want to talk about it. I don't want to sit around here and think about him. I want to get out of here, James, and do what I do best. I want to just get on with my life. It's not my fault that he's dead.'

James frowned.

'No one ever said that it was, Sirius,' he said slowly. Sirius blinked.

'No, well, it's not. He's the one who hung off Bella's every word. He's the one who swallowed our mother's theories and beliefs. It's his own stupid fault. I knew he couldn't handle it. I knew he'd want out sooner or later.'

James didn't know what he could say, but he sensed that he should say something.

'I'm sure you did all you could,' he said consolingly.

'I did,' Sirius said; but for a second he didn't sound so sure. 'I did …'

'Sirius?'

'It's just that … I mean, he was just a coward, that's all he ever was, and he would never have stood up to them, not like I did. He couldn't.' Sirius' thoughts seemed to tumble out of his mouth before he had time to censor them. 'There was nothing I could do, James. He wouldn't have let me. Even if I had tried, I couldn't have helped him.'

'I think you're right, Pads,' James agreed solemnly. Sirius caught his eye.

'Do you?' he asked desperately. 'Do you think I did the right thing?'

'I'm sure you couldn't have done anything else,' James said.

'But he was my brother. I should have tried …' but Sirius trailed off after that, unable to speak. James understood. He waited.

'I … should have … should have done something.' Sirius said disbelievingly. 'I should have … but I just cast him aside, like he didn't matter, like family didn't matter … and I never told him …'

'Never told him what?' James asked.

'That it wasn't his fault,' Sirius murmured. 'When I left. It wasn't his fault.'

'Of course it wasn't. He would've known that.'

Sirius didn't reply. He just shook his head.

'It's not your fault, Sirius. It's this damn war, it's Voldemort, it's all this prejudice – that's what killed Regulus. Not you. You didn't do this.'

'Yeah, I know, I know.' Sirius sighed. 'It shouldn't even matter, you know. I left all that family stuff behind. But sometimes …'

'What?'

Sirius shook his head. 'Never mind.'

'No, what is it?'

'It's just … you're my best mate, James, and you know it. And I'll always be there for you no matter what.' James nodded in agreement. 'But sometimes … Reggie was my brother. Sometimes I feel guilty that I never let 'brother' mean anything more. That I didn't put him before my mates. No matter what you say, sometimes blood is important … or, at least, it should be …'

James nodded again; although he sensed that, as an only child, he was well out of his depth on this one.

'I don't know, James,' Sirius continued soberly. 'I guess I always thought that Reggie would be there. The annoying little brother who never went away.'

James patted his friend on the back.

'We'll get them back, Padfoot,' he said, reciting one of their mantras from their marauder days. 'We'll get the bastards who did it.'

Sirius caught his eye.

He grinned, suddenly and without warning.

'Yeah. Yeah, we will. I owe him that.'

Please review! Also, I'll leave the punishment for breaking the marauder's code to your wonderfully overactive imaginations ...