A story of two young adults stumbling through life's biggest challenge, told in an overarching narrative and non-chronological vignettes interspersed throughout, and measured by the phases of the moon.

A/N: As should be obvious from the summary, this is an AU of canon. Changes during the Marauder era resulted in the events of the First Wizarding War taking a differing turn - the Light received no warning about the prophecy, leading to the Potters' deaths occurring when Harry is only five months old, and Remus' close friendship with Lily Evans led to his his earlier maturation, which gave him the confidence to stop Sirius from making the biggest mistake of his life, namely going after Peter Pettigrew. That's left two twenty-year-olds a bit stuck with a baby they never asked for, but it's James' son, so it's pretty inconceivable that either Sirius or Remus would refuse to fulfill their best friend's wish. Putting it into long-term practice, though... well, that's what this story is about. Have no fear, relevant information will be given as necessary, including all the explanations on differences from canon and how those occurred.

The story will be roughly non-linear (I'm starting it with the epilogue, after all), however, most of the big events will happen chronologically relative to each other, and there will be several familiar faces popping up, though their involvement will be only in directly relating to Sirius and Remus' parenting of Harry. Their stories are depicted in my other works, for those who are interested.

Epilogue

21 June 2004
Waxing Crescent
(12%)

When Sirius and Remus arrive at St. Mungo's neonatal ward around eight in the morning on June 21st, they find Harry sitting on a wide chair, bent over his lap a bit. There is a large pale blue pillow almost engulfing his thighs, wedged between the armrests of the chair, and the most precious of things rest on it, holding Harry's attention as arrested as the golden glint of a Snitch zooming in the distance always does. He's clearly been up all night, Sirius can tell at just a glance – his robes are rumpled and creased, his hair is even wilder than usual, if that's possible at all, and there are bags under his eyes, exhaustion in the line of his back. It's a familiar enough sight that Sirius finds his lips tugging into a smile. But then Remus knocks on the doorframe to let him know they're there, and the look on Harry's face when he meets their eyes is such a mixture of stunned amazement, terrified excitement and boastful pride that for a moment Sirius stops seeing Harry at all – instead, he sees another young adult with wild black hair and round glasses, sitting in quite a similar chair with a similar precious load in his lap and the exact same impression on his face. It knocks the breath out of Sirius' lungs.

"Hi," Harry says very quietly, blue eyes sparkling from too much moisture behind his glasses, and the mirage shatters, leaving Sirius feeling like a deflated balloon, a familiar feeling twenty-four years old. He's learned how to let it pass without bringing him down, for the most part, but he always needs a moment to reorient himself and collect his bearings, to let the memories come and then wash away again.

He's made a promise, a long time ago, that Harry won't ever be James' replacement to Sirius, and he's kept that promise to the best of his abilities. He thinks he's done it well enough, all things considered.

"Hello, Prongslet," Remus speaks, because Remus always knows when Sirius needs him to step in. He's the first to cross the threshold into the room, to walk over to their amazing kid and run his fingers affectionately through Harry's messy hair.

Harry's got another nickname, has had it since Hogwarts, really, but this is the one that's just for them, for their once little, now significantly growing pack.

Harry's also, at almost twenty-four, far too old to have one of his parents (essentially if not in title) run their fingers through his hair, but he doesn't say anything about that, either. For all his boyish insistence on being seen as older than he is and never being treated as a girl might be (overt emotional displays somehow always end up being seen as feminising, it seems), Harry has in reality always been very open to physical affection. In some of the quiet moments, when melancholy and those black moods tug at Sirius and make him doubt himself and his place in Harry's life, Remus always likes to point out that this is a good thing, and that it is Sirius' doing, not only because he's inadvertently surrounded Harry by canines of various types, dogs and wolves, animals and Animagi, affectionate and social species all and one, but also because Sirius' own childhood had been devoid of something as important as that, and consciously or not, Sirius knew how much such a thing hurt, how much there is to physical affection, even at the parentally clumsy, too-young age of twenty-one.

Seeing the way Harry even leans a bit into Remus' touch, Sirius is glad he's done something right.

"Congratulations, Dad," Remus says, grinning. "Won't you introduce me to my great-nephews?"

"You mean grandkids," Harry replies, smile morphing into a mischievous grin. "You know you raised me as much as Sirius did; you deserve the title."

"I'm too young to be a grandfather," Remus complains with a shake of his head, though they all know he doesn't actually mean it. "I've barely gotten used to being a dad, you know."

"Right," Sirius snorts, stepping into the room to join them. "Don't even pretend you think you're new at it. As if I'd have ever pulled it off without you," he tells his best friend and partner in this great endeavour – they're still at it, even if their roles have reversed. It's the time for late babies, it seems, and early ones, too. Sirius can't complain either way; he was barely twenty-one when Harry had come to him, and he's quite comfortable with the idea that that's it for him, really, he neither planned nor wanted more kids, but at forty-four, he does find that he likes playing uncle to Remus' boys, maybe even something of a third wheel parent, when it's needed of him. It makes him appreciate Remus' role in his upbringing of Harry all over again.

"See, Moony? We all agree," Harry tells him, and it's enough for Remus to sigh and smile.

"All right, then, fine, you win."

"Now, proper introductions, and don't skimp on the pride," Sirius orders. "Soon enough you won't be able to claim their achievements for your own, so you better get plenty of it while you've got the chance."

It makes Harry laugh, because after everything that's happened in his life, he understands perfectly well what Sirius actually means with his words. They summon the two chairs by the wall, one to sit on each side of him, and Harry looks down with the soppiest expression Sirius has ever seen on his face – he is utterly in love with these two tiny, tiny people, and he's only met them eight hours ago.

"Moony, this is James," he says, sliding his hands with infinite care under the fragile head of the newborn to the left, dusted with dark hair and with eyes closed, skin still wrinkled and pinkish, and Remus is immediately there to accept the babe when Harry lifts him off the pillow. And Remus, like every other time Sirius has seen him hold a newborn, be it his own son or Lily's baby twenty-four years ago, settles the delicate thing against his chest and smiles that smile that never fails to make Sirius' breath catch in his throat from how gentle it is.

Harry turns back to the pillow and repeats the process with the newborn closer to Sirius. "And Padfoot, meet your namesake."

There's a lump in Sirius' throat when he accepts the little Sirius, when the tiny thing opens his eyes to squint up at him and shift a bit in his hands, and he remembers holding Harry like this, a quarter of a century ago, when his father had handed him in just the same way to Sirius. Remembers, too, that squalling, heart-broken, confused and afraid five-month-old that he'd fought so hard for, and had tried to do the best by that he could.

"All right, no way did you name them only that," Sirius declares to hide the tears that start stinging his eyes. "Out with it – what are their full names?"

Harry snorts and shakes his head as he leans over to run the tip of his finger against baby Sirius' closed fist. "You know us both too well, don't you?"

"How could I not? You're both as much my family as each other. Besides, we Blacks are a pretentious lot, and I know you're one whether your name is Potter or not."

It earns him a grin – Harry's always considered the various members of the Black family as his own kin (he's called Sirius' brother 'Uncle Reggie' since he was old enough to talk, after all), and perhaps that's the consequence of Sirius' hidden possessiveness coming to the fore, that he's allowed Harry to put the Potter name and history a bit more to the side than was perhaps advisable, but after the thorny road of parenthood they've all travelled, are travelling, or will be travelling, it doesn't seem like such an inexcusable crime, compared to all the others. A little Black pretentiousness won't harm the Potter offspring, because, after all, they could be nothing but Potters, since Harry, for all his closeness to Sirius' family, is still a Potter in the end, in his blood, still the head of that Pure-blood house, once numbering only one, now gone up to four.

Pulling back, Harry turns his attention to little James in Remus' arms, as if he can't help himself flit from one to the other, as if he can't bear to split his attention, and yet he must. When he speaks, there's mirth in his voice.

"Castor James and Pollux Sirius Potter."

Remus loves it, of course, bursts into raucous though still quiet laughter. But then Sirius does, too, because somehow it's perfectly ridiculous and at the same time ridiculously perfect.

"Harry, you two are too cruel!"

Harry's grin is as bright as the sun.

"But it fits, Moony," Sirius reminds him. "They are twins, and I can't think of a more famous pair than the famed Gemini."

"'Dioscuri' is actually the more mythological term," Remus corrects. "But yes, it's definitely appropriate, and for all sorts of reasons. For instance, today is the last day of the zodiac sign of Gemini."

They grin at each other, because how can they not?

"They're going to be utter terror, won't they, Moony?"

"And they've already got their own nicknames, at barely eight hours old. Prongslet, I do think you two have outdone yourselves with this little mess."

"Right?" Harry agrees, and they all know they're talking about far more than just names that are appropriately pretentious and at the same time full of symbolism – the only proper way to do things in the Wizarding world. "We have done good, haven't we? I didn't think we could do this well."

"You two've done amazingly," Sirius confirms, placing his hand on Harry's shoulder, Remus doing the same on the other side. "We're so very proud of you, kiddo, and James and Mary would have been, too."

"Thanks, Dad," Harry whispers, bending his head into Sirius' shoulder exhaustedly, so that Sirius can wrap his arm around his boy's shoulder and hold him close, and it's possibly one of the most perfect moments of his life, with his son warming his side and one grandson's weight in the crook of his arm, with his best friend's warm eyes meeting his and his other grandson in his best friend's protective hold.

All things considered, Sirius doesn't know how they could ever have done any better than this, and for just one moment, one single moment since the day he'd taken Harry's trusting, innocent weight into his arms on Christmas of 1980, he doesn't feel that hole in his heart where James used to be, doesn't feel the shadow of the young man who had been more than even a brother to him hanging over them.

It's more than he could ever have imagined having in his life, when he'd said yes to being Harry's godfather, Harry's guardian and protector, Harry's second father, and he's never felt more humble – or more proud – than he does right now. It's a feeling he knows he'll protect with everything that's still in him, until the day he joins the one who should have, by right, been in his place.

He knows James wouldn't mind, though. And that's all he needs to be guiltlessly happy.