Harry's thoughts kept drifting back to Sirius Black during Flitwick's lecture on the Engorgement Charm.

It all made sense now, why Black was after him. But Harry still couldn't get his head around the idea that Black might be his godfather. After all, as Ron had pointed out in a panicked whisper when Harry had told them what he'd overheard, the role of a godparent was incredibly important in the wizarding world. Normally, it was a role given to siblings or to friends so close they were considered family…

That was the thought that sickened Harry. His own parents must have considered Black – the man who would one day murder thirteen people and escape from Azkaban just to try and kill their son – like a brother. They'd trusted him enough to make him their son's magical guardian, and he'd betrayed that trust by serving Voldemort. The thought was so abhorrent, so appalling that-

"Harry," Ron said suddenly, nudging his friend's arm.

"Huh?" Harry asked, shaking his head as he was pulled from his thoughts. He realised then that everyone around him had started to pack up their bags. Hastily, he followed suit, stuffing the parchment that was bare except for a few half-hearted scrawls from Flitwick's lecture into his bag.

Hermione and Ron hovered by his desk as they waited for him. Hermione looked anxious, though she forced a bright smile when she caught his gaze.

The trio hung back slightly until all their classmates had trickled out of the classroom, following far enough behind that they couldn't be overheard as they made for Hagrid's Hut.

"Listen, Harry, are you sure Malfoy was telling the truth?" Hermione asked in a hushed tone.

"Yeah," said Ron. He pushed open the door to the grounds, wincing slightly at the chilly air. "Slimy git's always talking bollocks. He could've just-"

"He didn't know I was there," Harry said in frustration, cutting Ron off. "Besides, he's made a jibe about it before. Right before I punched him, he said something about avenging my parents. And in potions. Remember? After the incident with Buckbeak. He said then that he'd hunt Black down himself if he were me. He's been baiting me. Waiting for me to ask - or maybe he assumed I knew - so that I'd go after Black."

"Yeah but he's just saying that so that you'll go after him and get yourself injured before the talentless prat has to face you at Quidditch again," Ron interrupted, shoving his hands deeper into his pockets in an effort to ward off the cold. He shot a half-grin at Harry, as he always did when he made a dig at Malfoy, only to freeze at the dark look on his friend's face. Then, his voice wavering slightly with uncertainty, he spoke again, "you're not actually thinking about going after him, are you?"

"Of course Harry's not going to do that," Hermione answered for him, though she sounded less certain that her assertion suggested. "Black's a fully trained wizard. And he must be capable of really advanced magic to have escaped Azkaban. Besides, even if Malfoy isn't lying about him being your godfather, why would you need vengeance against Black more than any of Voldemort's other followers?"

"It's not just Malfoy," said Harry suddenly, "Mr Weasley made me promise not to go after Black, right before we boarded the Hogwarts Express."

"But that still doesn't make any sense at all. There's got to be some part of the story you're missing. But I just don't know how we'd find out. We could look in the library maybe, there might be something in the archives about Black-"

"Or we could just ask Hagrid," Ron interrupted, as the ramshackle wooden hut came into view.

"Do you think Hagrid will know the answer," Hermione asked doubtfully.

"He probably will. He knew Harry's parents when they were here. Besides, he's the only person who'll actually tell Harry anything, so unless you want to dig through some ancient newspapers just in case they have anything about Sirius Black, this is the only option," he turned to Harry, questioningly, "what d'you reckon, mate?"

"Yeah," Harry agreed, a vague sense of relief pushing through the haze of anger and confusion that had been clouding his mind that morning. Hagrid was the best bet he had of finding out the truth. "I'll ask him. After class, though. Once everyone's gone."

It was torture to stand for an hour poking shredded lettuce down the flobberworms' throats but at last, when the rest of the students had rushed away to enjoy their hour of freedom before afternoon lessons began, Harry approached Hagrid.

Without any preamble, or even sparing the time to return Hagrid's smile, Harry asked the question that was consuming his thoughts.

"Why didn't you tell me Sirius Black is my godfather?"

"Harry! Harry, talk to us. You can't stay out here forever." Hermione said desperately.

Harry didn't respond. He kept his eyes fixed on the horizon, the autumn sun shining down onto the lake. There was a slight chill in the air and the gentle breeze caused ripples to appear. Harry pressed his knees against his chest, wrapping his arms around his legs almost as if he were holding himself together.

"You missed lunch," Ron said as he reached into his pockets and pulled out a couple of pilfered pumpkin pasties. He passed the pasties, wrapped in a crumpled napkin, over to Harry.

Harry shrugged. He took the offered food with a small smile though he made no move to eat it.

Hermione pulled her robes tighter around herself, shivering slightly as the wind picked up. "Aren't you cold, Harry? You've been out here for ages."

Harry shrugged again.

Truth be told, he was cold. He hadn't thought to bring his coat out with him, and he'd been sitting out by the lake for the better part of an hour, unwilling to be around people while he processed the tale Hagrid had told. But the cold didn't bother him. Anger raged inside him like a fiery inferno and it was almost nice to have the wind cool him down. Besides, it was easier to tell himself he was simply shivering from the cold and not trembling with grief and fury.

"Do you want to talk about what Hagrid said?" Hermione asked timidly.

Harry shook his head.

Ron and Hermione exchanged a helpless glance. Neither of them knew what to do in the face of Harry's silence. Then Ron dropped down beside Harry, offering company where words failed, and gestured for Hermione to do the same.

Silence overcame them again, as it had ever since Harry had wheedled the fully story out of Hagrid. Harry hadn't spoken a word since then, and eventually Ron and Hermione, on the advice of Hagrid, had left him alone to think things through.

Finally, with a worried glance at her wristwatch, Hermione's voice broke the silence, "the warning bell's about to go."

Harry didn't even twitch. He stayed in the same hunched position and continued to stare out over the lake.

"Come on, we'll be late for Herbology if we don't hurry," she tried again.

"I don't care about bloody Herbology," Harry burst out, speaking for the first time since he'd left Hagrid's Hut.

"Harry, I know you're upset but-"

"But what, Hermione? But Herbology is more important than me being upset. You heard what Hagrid said. Black's the reason my parents are dead. He was their friend and he betrayed them. But God forbid I should care when a pot of Puffapods needs to be replanted."

"She didn't mean it like that," Ron said. He paused, as though waiting to see if Harry would respond with another outburst, but when none came he pressed on, "she just doesn't want you to get in any more trouble is all. You've still got a couple of weeksof detention left with Snape, you don't want to add to it from Sprout of all people."

At the mention of Snape, Harry's temper flared again. All the humiliation he'd suffered from his medical exam that week, all the snide comments Snape had made about the father Harry had never even met, all the attacks on Harry's celebrity status, that was all because of Black.

"I don't care!" Harry said angrily. "I don't care about detentions or trouble or Snape. Black's the reason I don't have parents. He's the reason I'm stuck with the Dursleys. You don't know what it's like, living with them. And I couldn't even leave this summer because of him. I had to stay there all summer."

Ron and Hermione exchanged a worried glance.

"Were they awful?" Hermione asked quietly. Her eyes flicked to his arms and back, and Harry remembered her questioning him about some bruises at the start of term.

"They're always awful," Harry said, feeling suddenly bone tired.

He looked back out over the lake. Though he couldn't see them, he knew Hermione and Ron were engaging in a silent conversation behind him. Out of the corner of his eye he saw Ron shrug slightly at whatever Hermione had mouthed but neither seemed willing to break the silence.

"Look, go to Herbology," Harry said finally, "Sprout'll be twice as annoyed if we all skip. Tell her I've got a headache or something."

Hermione stared at him inscrutably for a long moment then pushed herself to her feet.

"Seriously, I need to be on my own right now," insisted Harry when Ron hesitated.

"You sure?" Ron said uncertainly.

Harry nodded. He attempted a small smile but his mouth wouldn't cooperate. All he managed was a slight grimace.

Ron didn't look reassured. He stared at Harry for a long moment then pushed himself reluctantly to his feet.

Harry could hear them whispering furiously as they walked away but he didn't have the energy to care.

He stayed out by the lake for a good while longer, skipping stones across the water. Ron had taught him how to do it last summer at the Burrow, when they were paddling in a slow running river they'd ambled down to on a particularly hot August day. Ron's dad had taught him when he was small and he'd passed the skill on to Harry because Harry had no father of his own to teach him.

At once, a terrible grief overcame him. With a furious roar, he hurled the flat stone as hard as he could into the lake. Then he crumbled, collapsing his head into his hands. It was because of Black that Harry had had to learn to skip stones from a friend not a parent. Because of Black that the only family he'd ever known was the Dursleys; not that they'd ever treated him like family.

Black had robbed him of a real family, of real parents, the moment he'd decided to betray his friends to Voldemort. The longer that thought echoed around his head, the angrier he grew. A hatred such as he had never known before was coursing through his veins like a poison. Pressure built up in his chest and his eyes stung with suppressed tears.

He would find Black, he swore to himself, running a hand through his messy hair. He would find Black and he would exact justice for his parents.

Too amped up to sit still a moment longer, Harry pushed himself to his feet. Across the lake, other students were beginning to traipse out of the castle towards the greenhouses, or perhaps to Hagrid's hut. Ron and Hermione would be making their way to Divination now, ready to sit through their final double of the day in Trelawney's overly perfumed classroom. He knew he ought to join them; if he left now he'd probably even get there on time. Besides, he was already pushing his luck by skiving Herbology, there was no need to make his absence obvious by skipping the rest of his afternoon classes.

Except he couldn't face the thought of sitting on one of the chintz armchairs and drinking tea and pretending that everything was normal. Like his world hadn't been shattered to pieces in the space of twenty-four hours.

Yet, he also knew he could not stay by the lake for a minute more. He was overcome by an overwhelming need to do something, anything, instead of sitting there and feeling so… helpless. So powerless. Powerless against Black and his relatives and unable to gain control over even the smallest fragment of his life.

But he could gain control. He could find Black and exact revenge and maybe then he'd finally stop feeling like walls were closing in around him. Plans began to form in his mind, and Harry didn't not push them away. Perhaps he might have done on another day, on a day where he didn't feel so acutely aware of what Black had stolen from him.

He would find Black, soon, once he was a little bit better at offensive spells. Grim determination welled in his chest, and he started to make his way towards the castle, to the library to check-out a couple of books on duelling or to his dorm to read through his DADA textbook or down to the cloisters to wait for Neville so that he'd have someone to practice with. Ideas and plans raced through his mind at a dizzying speed, and he headed off without sparing a final glance back to the where he'd been sat.

Unbeknown to him, a black dog sat watching forlornly from the edge of the Forbidden Forest.

Severus was enjoying a piping hot cup of coffee when Minerva came to find him. He had been sat, quite contently, in the corner of the staffroom, listening with half an ear to the murmured conversations which hummed around him while he finished up marking the last of the fifth years' essays. His quill, which had been racing across the parchment, stilled as Minerva lowered herself into the vacant chair beside him. Taking in her grave expression, Severus pushed his marking to one side and turned the full force of his attention on her.

"I spoke with Albus yesterday evening," she said in a quiet tone. Her face looked worn and her grey eyes seemed, for a moment, to shine with the same sorrow Albus' had. "He gave me a copy of Poppy's notes from Potter's visit."

It was only his years of occlumency training that enabled him to suppress a wince. Those notes. The ones that laid bare a lifetime of mistreatment for the boy Severus had sworn to protect. Notes that, though no more than ink on parchment, had forced him to examine every preconceived notion he held about the boy.

Sleep had eluded him the night before, as he'd painstakingly thought through every interaction he'd ever had with Potter, in a desperate effort to work out how he'd missed the signs which in hindsight seemed so blindingly obvious.

"How did we miss it?" Minerva asked, unknowingly echoing Severus' own ruminations. Then, after a moment of silence, she continued apprehensively, "Albus- Albus said Potter's family were responsible for his … for his injuries."

"Albus seems certain of it, though Potter has yet to say anything conclusive on the subject. Unfortunately, the pattern of repeated injuries over a long period of time is indicative of abuse from a member of the household. And … Albus admitted to having … doubts about leaving Potter with Lily's sister. Apparently he knew that he'd be subjecting the boy to a difficult upbringing … though he was … adamant that he never believed they would harm him."

Minerva's eyes flashed with sorrow and she looked away from him, her gaze fixed on her hands. Her whole posture seemed defeated, and when Severus' eyes had met hers, he'd recognised the hint of another emotion, the same sentiment that had dimmed Albus' blue eyes, behind her sadness. He recognised it well, for it spread through his body like a poison every time he glanced at his left arm. Guilt.

"I told Albus not to leave him with those despicable muggles. I told him they weren't a suitable family to raise Lily and James' son. I told him..." she broke off, her voice breaking slightly. After a few agonising seconds, she managed to school her face back into its normal, serious expression, though her eyes still shone with a weary grief that even her best efforts couldn't mask. When she spoke again, her voice was heavy with self-reproach, "I watched them for a whole day. I warned Albus they were the worst sort of muggles. But I never thought to check up on the boy. Even when he elected not to return home over the holidays, I didn't consider that there might be a reason why he'd rather stay at the castle. I just- I never- I didn't believe that any sister of Lily Evans would be capable of harming her child." Her voice hitched slightly and she fell silent.

There was nothing Severus could say to that. Even he had been surprised, and he'd known Petunia when she was a shrill little girl and when she was a bitterly jealous teenager and as she was becoming a spiteful adult. Sure, she may have made Lily cry with cruel comments and an absolute refusal to reply to her letters, but Severus had always assumed she loved her sister, deep down.

A slight sigh, one that spoke volumes of his own regrets, escaped his lips. He raised his hand, as thought to press it against his temple, but he lowered it again before the movement was even half-completed.

Silence followed, shrouding them both in tense quiet that made every breath seem unbearably loud. Minerva clutched at the handle of her teacup, her weathered hand white with the force of her grip. Her head was bowed slightly, as though the weight of her own guilt and shame was bearing down on her, and her eyes appeared dimmed by the knowledge of their negligence. Not for the first time, Severus wished he could offer some comfort, but there was none. Nothing he could say would rid them of the knowledge that for two years Lily's son had been in their care without them noticing anything amiss.

But, Severus reminded himself, no amount of self-flagellation, no matter how deserved, would change their mistakes. No, all they could do now was seek to make amends for their past mistakes. To atone, as he had been attempting for almost twelve years.

With that thought in mind, Severus broke the silence, "Albus has asked that I look out for the boy until a suitable guardian can be found."

To Severus immense surprise, Minerva's expression did not change. There was no gasp of surprise or any exclamation of outrage. Instead, she took another sip from her teacup, draining it of its contents, and placed it gently back onto the saucer. With a steady hand, she reached for the teapot that had popped into view and refilled it, adding a teaspoon of sugar and a dash of milk while Severus sat in a confused silence. "Albus told me," she replied at last, "we debated the matter at great length. So, if you're waiting for me to offer my criticism of that decision, I'm afraid you've missed your moment."

"And you're… supportive of his plans?" He couldn't quite keep the note of absolute astonishment out of his voice.

"You, of all people, ought to know by now how difficult it is to persuade the Headmaster otherwise once he has an idea in mind." Though her expression remained severe, her tone was light, and just for a moment she seemed less defeated. Then the weariness re-entered her voice, and she continued with a heavy heart, "besides, you were the only one capable of seeing what the rest of us did not. You have proven yourself, more than I or any of the other Professors, to be capable of looking out for Potter."

There was an awful hollowness in her voice and, embarrassed at bearing witness to his old Professor's grief, Severus looked away. His eyes traced the room, observing the little habits of his colleagues with a spy's scrutiny, until Minerva drew his attention back to her with a light cough. Though her face remained weary, there was a steely undertone behind her mild manner, "however, you ought to remember that, regardless of any assignment that Albus hands out, Potter is still a member of Gryffindor house and as such, I am ultimately responsible for his welfare."

"Of course," Severus agreed, unable to take offense at the implied threat. It wasn't as though Minerva had any reason to trust him with the boy, he'd expressed nothing but disdain for Potter's spawn since he'd started at the school. Even now, it was not out of fondness that he was taking on a more active role in protecting the boy, but a sense of duty.

Minerva, seemingly satisfied with his easy acquiescence, allowed silence to settle over the pair for a few moments, before launching into an update about changes to the prefect rota when some of their colleagues sat down within hearing range. Then, once she'd finished the last of her tea, she rose to prepare for a meeting with Madam Pomfrey.

Severus remained sat there long after she'd left, his marking all but forgotten. His conversation with Minerva seemed to have opened a floodgate, for all the thoughts he'd worked so hard to suppress came rushing back and he found himself struggling with the enormity of the burden Albus had placed on his shoulders. A glance at his pocket watch told him he had less than an hour until Potter was due to arrive at his door, but Severus was still at a loss of how to deal with his old nemesis' son.

He'd be the first to admit that he lacked any fondness for the boy, who had served as a constant reminder of all his greatest mistakes from the moment he'd set foot in the school. Besides, he was hardly known for his kindness or ability to offer any meaningful comfort. Even with students in his own house, crying first years were quickly passed over to the prefects and any Slytherin in need of emotional support was sent swiftly over to Poppy's office. He was willing, as Head of House, to offer advice and to discipline his erstwhile students, but never to offer play the role of guardian. Not in the way Potter needed.

But Albus had asked him to look out for the boy and Severus was hardly about to let him down. Especially when it was his fault Potter had ended up with dumped on Petunia's doorstep.

And, as a desperate part of him hidden somewhere in the depths of his soul acknowledged, he owed it to Lily. Not just because of his role in enacting the prophecy, but because she'd offered him friendship and support when he'd been a scared child in a situation not all that dissimilar from Potter's.

She'd made those awful years pre-Hogwarts bearable, had been outraged on his behalf at the bruises that adorned his pale skin and held him when it all became too much.

And now he would do the same for her son. He would find out the whole truth and send him to the right people for support. Though he did not, nor would he ever, care for the boy, he would see him through this. At least until Albus relieved him of that duty.

With a script of how Potter's detention ought to go forming in his mind, Severus began to make his way back to his office.

Somewhere in the castle, perhaps several corridors away, a clock chimed seven times, each clang cutting through the general hum of hundreds of chattering students making their way between the Great Hall and the Library and each of the four common rooms.

Harry ignored them all, weaving through the ambling pupils with a sense of purpose as he descended deeper into the depths of the castle. When he reached the dungeon, he did not follow the familiar path that would lead to Snape's office, where he was due for his detention at that very moment, but instead he carried on down towards the cloisters.

He had not intended to skip his detention, but somehow his legs seemed to have carried him away from that room and the terrible conversations it would bring without any conscious decision on his part.

Perhaps he ought to care, and indeed a part of him knew that Snape's wrath would at some point descend upon him, but he couldn't find it in him to care. Not when he felt so disconnected from the rest of the world, as though he had been trapped in one of the Potion Master's vials, separated from everyone else by a thick wall of glass. A sense of purpose ran through his veins, and anything that did not involve vengeance on Black had ceased to exist to him.

What did it matter if Snape was angry? Or what the consequence would be when Sprout or Trelawney inevitably reported him for skiving their classes earlier that day? Those problems were trivial, insignificant in a world where Black was still at large. And it was so much easier to focus all his energy on Black, to direct his hurt and anger and fear at a single source, than to contemplate the knowledge that Snape, of all people, now held.

Pushing all of that to the back of his mind, in Harry continued down to the cloisters with a single-minded focus and a defence textbook in his hand, ready to practise with Neville until he was ready to face Black.

That was all that mattered now

Severus waited, fixed at his desk with his face carefully schooled into a neutral expression, for forty-five minutes before he accepted that Potter simply wasn't going to turn up.

Try as he might, he couldn't bring himself to feel more than a slight annoyance at the boy. Why would he show up when he expected to be humiliated by his least favourite Professor about a secret that he'd kept as long as he could remember? No, Severus was hardly surprised by the boy's disobedience. Though it was unexpected, if only because Potter, for all his many, many flaws, was hardly a coward, and was generally known to face difficult encounters with his head held high and an air of smug defiance.

That was what Severus expected from the boy. Then again, the first month of term had taught him to re-examine all his preconceived notions about Potter.

But what to do now, Severus wondered to himself, feeling out of his depth for the hundredth time that day. He could hunt the brat down, though searching through the castle for a student that did not want to be found was an arduous and demeaning task at the best of times. Besides, not much good would come from that. If Potter was in such a state that he was willing to risk Severus' wrath by skipping his detention, then he doubted any conversation the two would have would be conducive.

No, it would be better to simply leave the boy alone until tomorrow. Perhaps he ought to have done that anyway. Maybe he should've given Potter a day to think and recover some of his wounded pride. Not for the first time, Severus cursed Albus for giving him this responsibility. How was he supposed to know what the best way to reason with a scared and belligerent Potter was? It was hardly like he'd ever given much thought to the brat's emotional welfare before. And it wasn't as though Potter was rushing to give him any clues. Indeed, Severus had no doubt that as far as the boy was concerned, the best response from him would be for him to ignore the whole ordeal.

But Severus could not do that.

With a sigh, he reached for a quill, freeing his fingers from the interlocking grasp they had been clasped in for the past ten minutes. Though he did not yet have a particular need for it yet, he reached into his desk draw and withdrew a fresh sheet of parchment, waving his quill with a flourish as though the act of preparing to write would magically summon the necessary words. When the words proved not to be forthcoming, he settled for tapping his quill against it in a vague rhythm as he considered what to write. He still needed answers that only Potter could provide, but he was unwilling to wait another day to engage in a struggle against a sullen Potter for such information.

He wanted answers. More importantly, he wanted to be a step ahead as he normally was, rather than feeling as though he was constantly playing catch-up, as he'd felt ever since he'd first considered any sinister reasons for the bruising on Potter's arm. Perhaps then, if he wanted to regain control of the situation, it would be better to go into a conversation with Potter armed with the cold, hard truth of the situation, rather than relying on Potter's no doubt distorted version of events. But where to find that…

He could pay a visit to the Dursleys. But as quickly as that thought entered his mind he discarded it. While there was no doubt he'd pay them a visit in due course, he was saving that endeavour for when he already knew exactly what they had done, and, more importantly, for when he had a plan for vengeance in mind. So, if not the Dursleys, who else could provide him with the information he so desperately needed.

Not Molly Weasley. Her missive had made it clear that while she had her suspicions, she had little evidence to back any of it up. If she had, Severus doubted she would have left the issue alone. Yet, no one else had even had suspicions, or at least not ones they'd chosen to share with anyone. Severus liked to think that Albus would've investigated the matter if Arabella Figg had mentioned anything amiss.

Still, perhaps Arabella was the place to start, if only because she'd spent over a decade observing the boy.

A glance at his watch informed him that it was barely past eight, still early enough to pay her a quick visit. He doubted she'd have other plans, not on a dreary Thursday evening in October. Quickly, he scrawled a note to Albus, asking him to inform Arabella of his imminent arrival and asking that his pensieve be delivered to his office before he returned, before moving through the secret door beside his desk that led to his rooms. There, he gathered everything he would need with a practised ease, summoning the necessary vials and stowing them in his magically enlarged pockets.

With a final glance around the room, he set off, moving swiftly through the castle and out into the grounds, his cloak billowing out behind him as he pressed on against the wind, towards the nearest apparition point.

Then, once he was outside of the castle grounds, he turned sharply on his heels and disapparated. Though he was, after well over a decade, accustomed to the unpleasant sensation of being forced through a very tighter rubber tube, he still had to swallow back his nausea as he landed on the pavement of a bland suburban street in Little Whinging.

Despite his urge to gag, Severus could feel a sense of excitement rising within him. Finally, he was one step closer to finding out the truth. With that in mind, he hurried down Wisteria Walk, his eyes peeled for Arabella Figg's house.

A/N Sorry for the long delay in updating, I've had this chapter pretty much completely written and ready to post since March 2020, but with lockdown and the pandemic I never had the chance to edit it properly. I promise that I'll never abandon this story, though given the uncertainty at the moment, I don't know how frequently new chapters will be uploaded. Thank you so much to everyone who's read this far, and especially to the people who've followed, favourited and reviewed! Seeing the notifications come through has made my lockdown that much more bearable. Stay safe!