Disclaimer: I obviously do not own any of the characters or scenes that you recognize.
This story jumps into things rather quickly, though a back story of Regulus and his family's past will unfold as you read. Harry is only sparingly in the first several chapters but will have a more central role soon after.
"Carina has a boyfriend," Regulus remarked in a poor effort at sounding casual at the breakfast table.
His wife, Maliah, smirked, "Finally figured that out, did you? She wrote to me about Andrae weeks ago."
"And you didn't see fit to tell me?"
"I promised I wouldn't," she answered simply.
"Shouldn't you have known before us, dad? I mean, you are one of their professors…"
"Children should be seen at mealtimes, not heard," he answered just as his mother would have done, though his remark was without any of her malice. "Eat your breakfast, Caelum."
The eleven year old boy sniggered, "Since when can I not talk while we eat? You just don't like being the last to know things."
"No, I don't."
"Who would want to date my sister anyway? Ugh."
"It seems at least half the boys in school of late," Regulus answered grumpily. His children were growing up much too quickly for his liking, "Andrae is a fifth year."
"I suppose Carina Sirius is living up to her namesake then, isn't she?" Maliah teased.
Regulus winced. His brother's former popularity with the opposite gender was certainly not why they had named their daughter after him.
"He's a half-blood," Regulus remarked offhandedly, earning himself a warning look from his wife.
"That doesn't matter, does it?" his son asked, looking between them.
"No, there's no difference," Regulus answered firmly. Maliah visibly relaxed. "But his sudden disappearance could be more easily covered up if he were muggle-born-"
"Regulus!" she laughed, "You can't go making an example of this boy! Carina would only rebel by finding someone worse to date."
"He's an average student at best. Carina is much smarter and she's only fourteen. Fourteen, which is too young to be dating in the first place."
"She will be fifteen in little more than a month. You're going to have to accept the fact that she is growing up."
Regulus jabbed his fork into his eggs a bit more forcefully than necessary, causing his wife and son to exchange amused glances. Excusing himself from the table, he stood, intent to get some grading done before his first class that morning.
"Can I go to school with you, dad?" his son asked, surprising neither of them. Caelum had always enjoyed sitting in on his father's classes, especially when they were given practical exams.
"You will begin Beauxbatons soon enough. You have your own lessons to attend to."
"Please, dad? I only want to watch the seventh years' last attempts at producing patronuses. I can work on my lessons during your other classes… Please?"
Regulus fully intended to say, "No," as it was the end of the term and he had a lot of grading he needed to get caught up on, which he knew would be more difficult with his son there. One look at Caelum's hopeful expression though and he heard himself agreeing.
"Go quickly and change into something more presentable," he directed as Caelum was still in his pajamas. "I'll warn you though, a lot of the seventh years are still at Hogwarts for the Triwizard tournament. It is unlikely you will see many corporeal patronuses today."
Caelum snatched the toast from his plate and hurriedly left to get dressed. Regulus watched the back of his head disappear up the stairs and resisted the urge to tell him to run a brush through his hair before coming back down.
He tried not to be overbearing towards his children as his parents had been. Over the years he had managed to let go of the worst of his family's prejudice and customs. Ensuring his family looked their best before leaving the house was too ingrained in him to let go of anytime soon though.
Aside from not seeing any harm in taking pride in the way his family presented themselves in general, they were also Blacks. The majority of France may not be as familiar with his family's reputation, but he wouldn't be forgetting it anytime soon.
He looked back at his wife to find her watching him. At his questioning look she grinned mischievously, "The entire day to myself? However shall I spend it?"
"This is going to be expensive, isn't it?" he asked wryly.
"Best not to think about it, my love," she whispered before giving him a swift kiss and following her son up the stairs to finish getting ready.
Regulus had a fairly good day of teaching at Beauxbatons Academy. His first class had been fourth years, which included his daughter. He had been able to pull her aside after her final exam to have a nice chat about why she was much too good for the Andrae brat. It went about as well as any discussion of that nature between a father and teenage daughter could.
His day got immensely better when said daughter's boyfriend graced him with his presence in his very next class. With the OWL equivalent not being taken at Beauxbatons until sixth year, he had more flexibility in testing his fifth year students.
He had asked for a volunteer to be the target for which the other students took their practical exam. When no one offered to be their guinea pig, he took great satisfaction in volunteering Andrae. It was clear by his classmates' reactions they understood the implication of why he was chosen.
It was only in good fun, of course. He cast enough protective spells to ensure no student would be injured in his classroom. Still, Regulus couldn't deny it had been fun watching him squirm. It was well known that he was a bit overprotective when it came to his children. Despite what his wife said, he couldn't think of any good reason not to 'make an example' of his daughter's first boyfriend. Even teachers had their reputations to maintain, after all.
His last class had been bittersweet as it was of seventh years and likely the last time he would ever see some of those 'kids'- who were technically adults now. He had taught most of them since they had been eleven, the same age Caelum was now. He had watched them as they learned the most basic of disarming spells until now as they were demonstrating various levels of success in casting patronus charms.
The graduating class this year had begun their education at Beauxbatons in the same year he started his teaching career. It made him feel extremely old to think about.
As Regulus returned home with Caelum (Carina had unsurprisingly opted to return home with her friends) that evening he felt an unexplainable sense of unease. His left forearm still ached on occasion from malaise, though it had not properly 'burned' in well over fifteen years. He thought perhaps he was being paranoid, but couldn't quite shake the feeling that something terrible was looming.
Just as his son was trying to talk him into playing a game of 'snitches only' quidditch before dark, it happened. His left forearm burned - a summons. It was not as agonizing or demanding of attention as it once would have been, but certainly enough to make him uncomfortable. Of course, the discomfort was nothing compared to the anxiety he felt.
'Padfoot' impatiently waited for Remus outside Sturgis Podmore's house.
After listening to Harry recant the horrors he experienced in the graveyard, he left him less than an hour later, to go and 'round up the old gang' on Dumbledore's orders. It was necessary, of course, but he still felt guilty for leaving Harry so quickly.
He tried to tell himself that it didn't matter that he left, that Harry understood. He knew he could have only stayed in the capacity of 'Padfoot' anyway and would not have been very useful to his godson. Besides, he'd left Harry in the care of Molly Weasley - a woman with more parental instincts than Sirius could ever hope to have. None of that could make him forget the disappointment he had seen in Harry's eyes as he left him.
Making matters worse was that he was equally useless in the task of recruiting the old members of the Order as he had been at comforting Harry.
Considering his presumed status of 'Voldemort's Right Hand Man', and an Azkaban Escapee, he couldn't argue Remus' point that it was best for him to stay hidden in his dog-form while he explained the finer points of Voldemort's rebirth to the former Order members.
He was pulled from his miserable dog thoughts when Remus returned.
"Ready to go, Snuffles?"
Sirius, the dog, yelped in agreement before leading Remus into a copse of trees where he could transform back into his human form.
"How'd it go?" Sirius asked, once transformed.
"As well as can be expected. He is eager to hear from Dumbledore."
Of course he was, Sirius thought. The first Order meeting couldn't happen fast enough.
"Does Podmore still have that awful haircut?" He wondered aloud.
Remus' lip twitched, "It looks thatched as ever," he confirmed. "How did Harry seem to be handling things? You never really said."
Sirius shrugged, "He's a tough kid. He's been through so much though… I thought I might see about keeping him with me this summer- away from the Dursley's. Do you think Dumbledore would allow it?"
"Only one way to find out," Remus answered thoughtfully. "I think it's time to call it a night though. I could barely get Podmore to come to the door and he's always had a habit of staying up later than most."
"Not to mention, we've pretty much visited everyone who was in the Order the last time who is still alive…"
"Impressive statistics," Remus sighed glumly.
"Yeah," Sirius agreed. "Are you going back to your place in Yorkshire?"
Remus nodded, "You're welcome to come with me if you need a place to stay."
Sirius hesitated, "I thought I might check out Grimmauld Place," he answered with obvious distaste. "Aside from Hogwarts, it's probably the safest place in Britain, and its been left empty since my mother passed."
Regulus pushed open the front door of number twelve Grimmauld Place with a profound sense of sadness. He gave a passing glance to the deteriorating furnishings and portraits as he made his way up the stairs to his childhood bedroom.
Despite the age of everything, it was in relatively good shape. He had visited shortly after hearing of his mother's death. Upon his visit, he had been happily surprised to find Kreacher still alive and took him back to France with him.
Sometime later, the house elf requested to be allowed to see to both houses. Not wanting his childhood home to deteriorate further, Regulus agreed. Kreacher had been apparating himself to Grimmauld Place every couple of weeks to dust and take care of any magical infestations that arose ever since.
Regulus had always been less thrilled to visit. To him, there was a fine line between tranquility and loneliness, and no place toed that line better than Grimmauld Place.
He had not come here for peace or even solitude tonight. In truth, he didn't know why he had come at all. He could have sent Kreacher to check on the locket, the locket that he had risked his life in exchange for all those years ago.
He caught sight of himself in a mirror on the second landing and was struck by how little his appearance had changed since the last time he had visited there. He had been spared from the undesirable traits of pre-mature graying or hair loss, and his hair was kept only slightly shorter than it had been in his youth. His skin remained smooth and unwrinkled. His eyes, still gray, though he liked to think they looked kinder than they once had.
He had inherited all of the Black family's classic features. It occurred to him that his looks were the only thing left in his life that connected him to the family he had been born into.
He didn't exactly believe in fate, but there was no doubt something more had been at play that night in the cave. How else could a planned suicide mission have turned into a means of escape from a life he had come to hate?
He had gone from parroting the beliefs of his family, to pledging his life to the Dark Lord. Soon after, he dedicated his life to finding a way to defy Voldemort. Discreetly, of course. He had no intention of making his family pay for his mistakes.
After his stint in the cave, he traded in his life of living for any sort of cause. He exchanged it for one with a much greater purpose and never once regretted it. That didn't mean he didn't feel guilt for his good fortune, never more so than when Sirius had been sent to Azkaban for a crime Regulus knew he would have died rather than ever commit.
Why had he felt drawn to Britain now? Tonight of all nights, only hours after his left forearm had burned for the first time in over a decade. Had he lost his sense of self-preservation?
It wasn't as if Voldemort could have used that horcrux to return to a human body. Aside from having already been destroyed by fiendfyre, the Black's ancestral home was practically a fortress. He and his father added every practical protection to the already well-protected house when Regulus' loyalty to Dark Lord had begun to waver.
He left the remains of the locket hidden in his old bedroom in the relative comfort of knowing that Voldemort would never be granted access inside the Black ancestral home, and that none of his death eater family members would know to look for a horcrux there. As far as he knew, no one else even knew there was a horcrux to find.
If he were keeping a tally of all of the things that caused him to feel guilt, not telling anyone else about the horcrux was quickly nearing the top. Unfortunately, at the time of his 'death' there hadn't been anyone he could trust with the information who wouldn't have tried to arrest or kill him on sight without bothering to listen to what he had to say. The exception being those whom he couldn't bring himself to endanger further with the information.
If the death eaters had truly been called to return to Voldemort's side tonight, it undoubtedly meant that he had managed to return to his human body. Regulus may not have dedicated his life to ensuring there weren't more horcruxes, but he would never forgive himself if Voldemort found a way to retreive and repair Slytherin's locket to do it.
As he reached his old bedroom, he fondly read the plaque that still hung on his door. 'Do Not Enter without the Express Permission of Regulus Arcturus Black,'. He could still hear Sirius taunting him when he hung it up after his second year at Hogwarts.
Leaving the sign, he unlocked his door and walked inside. He did his best to ignore the obvious pureblood obsession of his previous life and walked directly to his desk.
Pulling open the top most drawer, and undoing several protections, he eventually revealed what he had been searching for.
The remains of the locket were just as incinerated yet ominous as he remembered. He closed his eyes in both relief that the locket was still there and in shame.
He hadn't had to feel guilty about keeping the horcrux to himself when he destroyed the "only one" that existed. He had little choice now but to assume that had never been the case.
'Padfoot' led Remus towards Grimmauld Place with no small amount of trepidation. The house had only ever been marginally more welcoming than Azkaban and if not for the dementors, Sirius thought he might prefer the prison.
According to Dumbledore his mother had died a decade ago. He was the last surviving male of a family he hated. Any hope of the Black family's legacy surviving rested with him.
He vowed to use every contraceptive known to wizard kind, should the opportunity to reproduce present itself. The Black family deserved to die out. They were bigoted, arrogant and cruel- and prided themselves on those qualities as if they could actually be considered admirable.
It would be his last great act of defiance towards the family he despised to ensure the family name died with him. His mother of all people, deserved nothing less.
There was no telling what sort of disarray they would find the house in. Kreacher had probably died by now, leaving behind a rotting corpse that Sirius was sure would only add to the decaying furnishings. If Kreacher was still alive and on his last leg, it wouldn't take much for him to help him on his way out. Merlin, he hated that elf.
Kreacher would parrot the beliefs of his family about pureblood supremacy, without ever giving thought to the fact that it was those purebloods he loved so much who forced him to punish himself whenever he disobeyed them.
His greatest aspiration in life had been to have his head chopped off and mounted to a wall in the stairwell of the Black's ancestral home. He was fanatical and demented- in short, the perfect elfin match to the 'Noble' and Most Ancient House of Black.
Regulus had called it taking pride in his work.
Regulus. While it would have been difficult to return to Grimmauld Place in any situation, thinking of his brother made it physically painful. Somewhere in his chest region there was an ache- a hollowed space never to be filled again.
Their parents had likely only reproduced to ensure the Black name lived on, as was their duty.
To his mother they were the brats who caused messes in the house of her fathers and were constantly risking her reputation with their tomfoolery.
To his father they were putty, requiring both instruction and punishment to mold them into a near replication of himself.
There was no need for Sirius nor Regulus to have opinions, for they always agreed with whatever their parents thought.
Until Sirius didn't.
The give and take of tolerance and discipline in his childhood was replaced by animosity and resentment in the years after he began Hogwarts. He could only imagine the intensity of their loathing after learning he had joined The Order of the Phoenix- that he would willingly take up arms against their 'only' son.
There had never been any love between Sirius and his parents, but he and Regulus had been close once. In a family that resented their presence, there was solace in having each other.
Of course, even that changed once Sirius left for school and was sorted into Gryffindor. After his parents learned of his sorting, they became less indifferent towards their youngest child in favor of being more manipulative.
Regulus died before he was old enough to realize the extent in which he was misled. Then again, he was a Black. Maybe Sirius was being overly optimistic to think it would have made a difference. He had certainly never been brave. He had hid behind Sirius in their youth, behind his gang of Slytherins at school, and behind a mask as a death eater.
He had been easily influenced and a coward. He had also barely lived long enough to see eighteen.
Sirius transformed into his human form and approached the door of number twelve Grimmauld Place.