Author Notes: There is one Original Character in this - Flintoff - but he has one minor part in one scene only.

This story is not yet finished, but it will be (some time). There are two more chapters left. It's been such a long time since I wrote any of this that I've got to get my head back around it and the canon before I can write those final 1,000 words or so.

The Tortured Soul

by purpleygirl

'...my grief lies all within...
[and] swells with silence in the tortured soul'

— Richard II

1. What happened to listening at the door?

Harry had been dodging Slytherins for what felt like hours as he waited in the torchlit dungeon corridor. The things he did for his friends. He had caved into Ron's pleas, but he wasn't the only one eager to know whether the rumours were true. Nearly the whole school was buzzing with the idea of Snape leaving.

Another gang swaggered by. Making sure the Invisibility Cloak was securely round him, he pressed back against the wall opposite Snape's office. A jagged stone dug into his spine. He checked himself from choking out a curse – just as a boy nearly lurched right into him. That one had been close. Did all the Slytherins compare hexes everywhere they went? If this was their idea of downtime, it was amazing the school's infirmary wasn't clogged up with them every day. He jerked forward as an itching jinx bounced off the wall next to him. It hit one in the back, and they roared with laughter as their friend scrambled to reach around. 'Four to me!' another shouted, and they jostled him, the boy twisting and scratching at his robes and yelling obscenities as they rolled off in the direction of their common room.

Harry sighed and leaned beside Snape's door. This had better all be worth it. The dungeon was getting colder as the evening drew in, and damper. He was regretting having skipped tonight's Quidditch practice for this. And now another set of Slytherins sounded to be coming down the stone steps. He got himself ready – and held his breath when he heard Lupin's low voice alongside the deliberate footsteps. At last. He tugged the hem of his Cloak tighter around him as Lupin, looking worn, came into view just behind Snape. They drew near.

'Let me make one thing clear, Lupin, I am not your friend now,' Snape's voice boomed as he unlocked his office with a flick of the wand. 'And I never was,' he said, flinging the door open and striding in.

Lupin stayed in the corridor looking in as though to enter would be entering a battleground unarmed. Harry eyed the distance he was giving the room, inviting him to take the chance Lupin was reluctant to. He couldn't do it, could he? Why not? He glanced in. It would be stupid to listen at the door, he thought as he looked back at Lupin wavering, and end up with only garbled words for his hour of dancing around Slytherins. At the very least it might be less bone-achingly cold and damp in there, and not as prone to passing hexes. His legs were restless, wanting to move – and then Lupin made the decision for him. He turned his hesitance toward the stairs, just for a moment. But it was long enough. Harry edged sideways, slipped around the doorway, and staked his life on the tall glass-fronted cabinet that looked down the room. His heart knocked on the unmoved wood.

Lupin came forward. He closed the door and kept it at his back. Standing only a foot from Harry, he was just as jittery; apparently he hadn't overcome all his doubts. But neither of them had seen Harry, and he released his breath. Now he wouldn't miss a thing.

Snape was a swarm of black robes at his desk. A difficult silence wove its way between them, building a web of three, with Snape at the apex testing it by snatching up parchments and thrusting them down in jagged piles. Harry was the first to give voice as he pleaded in his head, through the fury of pumping blood and shuffling papers, for one of the men to say something.

Then Lupin took a breath. 'Dumbledore told me you—'

'I don't want to hear it,' said Snape, shifting parchment around with greater determination. 'Perhaps – now I know I wasn't exactly myself when he fell – I may rejoin the Dark Lord after all.'

Harry saw Lupin blanch. 'You … you don't mean that.'

'Oh? But I have accumulated so much information over the years – I dare say he would find some use for it all. It would be the perfect gift for his return – and for his very generous act – don't you think?

There was a look of exaggerated triumph as Snape glanced up. It seemed to slide away easily on meeting Lupin's pale face, leaving a suggestion of self-disgust. Snape's gaze dropped to the papers in his hands; he tossed them onto the desk and slumped into his chair. 'I don't know what I think any more.'

As though this were his cue, Lupin moved from the doorway and sat opposite him, so that Harry now found himself looking at Lupin's back. 'If you want to talk, I'm here.'

Snape leaned away and swept his eyes over him. 'And that's why you are really here, isn't it? The interfering Headmaster at work again.'

'That's not fair, Severus. He's only trying to help.'

'Trying to cover his back, you mean. He knows if I left Hogwarts he would no longer be able to keep an eye on me.'

'He's worried about you. You're thinking about doing things that could get you into a great deal of trouble. You and I both know Voldemort wants you here, and if you left now … well, he wouldn't exactly be happy about it, would he?'

'If my well-being had truly been uppermost in Dumbledore's thoughts, he wouldn't have told me any of this in the first place.'

'Perhaps,' Lupin said, with a quiet inflection in his voice that suggested acceptance of Snape's statement.

But it must have shown clearly in Lupin's face, because Snape jumped on it immediately. 'And why are you suddenly concerned?' he said, and raised an eyebrow – Harry recognised it as mock surprise.

Lupin said nothing, his back stiffening, indicating he understood Snape's insinuation. After a moment Lupin bent his neck.

So the rumours were true! Harry swallowed carefully around the dryness in his throat, relieved his gamble was paying off. Lupin was at Hogwarts at Dumbledore's request to talk Snape out of leaving. The entire school had been talking about little else for the last few weeks, captivated by the idea of a Snape-free year; but with Voldemort back, Harry knew better: Snape was up to something.

After a few tense minutes of silence, Lupin seemed to believe it better to change the subject. But the new subject was the last one Harry would have chosen. 'I ran into Harry earlier. He told me about recent Potions classes. He doesn't understand why you're … attacking James more. It's upsetting him.'

Snape snorted.

Harry's stomach lurched at Lupin's betrayal. It would make Snape's day to think he had got to him. Harry had no choice but to listen with a sick feeling as Lupin ploughed on. 'He doesn't understand, Severus. If you told him, then—'

'Tell him! Are you out of your mind?'

'It would make things easier—'

'For whom?'

'For both of you—'

'Plainly you have not thought this through.' Snape leaned forward so that he was staring Lupin in the face. 'Do you really think Potter would be pleased to know? That either of us would find our lives here easier? Think, Lupin.'

'He would need time, but… You can't keep this from him, not forever.'

Snape straightened. 'I can and I will. Harry Potter shall never know. His knowledge of this would achieve nothing.' He turned his head. 'And I could not bear the way he would look at me if he knew.' For a moment he stared at a spot on the wall as though his downfall could be read in it; he snapped his gaze away and sat back. 'Dumbledore has already sworn to me Potter shall never hear it from him,' he said with renewed confidence. 'And the few others who know … apparently it is inconsequential to them – they've most likely dismissed it already. Minerva does not know. Neither does Black. At least Dumbledore had the foresight for that. And you … now you know.' His glare became suspicious, challenging. 'But Potter shall never learn of it.'

'I won't go over your head about this. Harry won't hear it from me either. I appreciate it's your decision to make.'

'Good.'

'But pretending it never happened won't make it go away. Every time you see Harry…'

Snape groaned and dragged a hand through his greasy hair as though the sight of Harry was so offensive that he sought to rid himself of even the thought of it.

'But you can't leave Hogwarts,' said Lupin. 'You and I both know that. Not with Voldemort returned these last few months and Dumbledore reforming the Order of the Phoenix.' He ignored Snape's scowl. 'We all have a lot of work to do – we need to convince the Ministry to believe us when we say Voldemort has returned, for one thing. So the sensible thing would be to get this out of the way between you. Harry will understand in time.'

Snape's blazing distrust was not as easy for Lupin to ignore.

'I won't say anything. You know that. It's up to you.'

Snape's suspicion twisted into anger. 'So how do you suggest I should put it? Something like, "Ah, Potter?"' He turned and looked beyond Lupin at some imagined Harry, luckily standing at the other side of the door. '"By the way,"' he said lightly to the other Harry, who took his matching dislike in stubborn silence, '"your father James did not really die after all…"'

It was Harry's racing heart that first heard the words; it hammered for his attention. Adrenalin nipped the back of his throat as he saw Lupin's hands fly to the arms of his chair. 'Well, with a little more tact than that, perhaps,' said Lupin in a broken voice.

'Tact?' Snape looked disgusted. 'All the more reason why he is not to know, don't you think? Ever,' he added, punctuating the word by leaning back in his chair with a creak.

Harry's head swam as the words sank in. Your father James did not really die after all. He heard them over and over, his reasoning trying to find the explanation, the loophole in them. But there was none; though Snape had said them in obvious mockery to an imagined Harry, they seemed to be meant. Lupin's reaction said they were true.

And Snape had sworn he would never know.

Harry tried to steady his breaths. He had to calm down. If they found out he was there – if Snape was so determined for him not to know about this – who knew what he would do. The worst he could do was take the knowledge back somehow, with some horrible spell, make Harry carry on thinking his dad was dead… But he wasn't! His dad was alive! He wanted to shout it out. He felt like he had just made the greatest discovery in the world right here, right underneath his own father's Invisibility Cloak. And though that world had just expanded unimaginably, it now seemed to hang over a precipice.

He squeezed his eyes to shut out the room, and with a burst of fear stopped himself just in time from leaning on the cabinet. He focused on calming his excited breaths so they wouldn't give him away. What a stupid idea it had been, sneaking in here, right past Lupin. But then he would never have heard. His heart thumped again. His dad was alive – but he felt he didn't yet own this knowledge – not until he was free and far away from Snape.

He opened his eyes. Still sat at his desk, Snape was now bent over it, head in one hand. '…running out of Dreamless Sleeping Potion,' he heard Snape say. 'That blasted Headmaster,' Snape spat. 'Why? Why did he have to tell me? What good does it do?'

'Perhaps it may have been better if … if he hadn't.'

'Fourteen years – fourteen years I've been carrying it without my knowledge. Carrying it at no cost. And now Dumbledore seeks to change that.'

'He doesn't want to change anything – he just wanted you to know the truth. You know how he is.'

'Maybe I shall cast a Memory Charm on myself.'

'Severus – it was only discovered a few weeks ago. It will get better, trust me.'

'Oh – and you would know?'

'When I was bitten—'

Snape made a derisive noise. 'I hardly think turning into a werewolf each month is comparable with—'

'I have had to get used to being something I ought not to be because of the actions of one man,' said Lupin in a firm voice.

They seemed to try to outstare one another, then Snape looked away. 'I have classes to prepare for.'

Harry heard Lupin sigh and saw him move to rise from his chair. He got up slowly, heavily, as though he had been on his feet all day and was in need of a rest, and Harry began inching his way toward the door, bracing himself to slip out as soon as the first opportunity arose.

Snape was glaring at a shelf. 'Dumbledore thinks I'm to make the Wolfsbane Potion for you,' he said as Lupin pulled the door ajar. 'But there isn't a full moon for another ten days – I'm sure you know. You've had a wasted journey.'

Lupin had turned his face, so that Harry saw how far he seemed to have sunk within himself; he had never seen him look so tired. 'That's not why I'm here—'

'I know.' Snape closed his eyes and let out an irritated sigh. 'Would that there were a similar potion I could take,' he said, and he produced a horrible, strangled noise in his throat.

Lupin opened his mouth, but seemed lost. As Harry edged his way out of the room, he glimpsed his curious expression: a kind of fearful concern. 'We'll talk again soon, perhaps?' he said. Harry didn't catch Snape's reply.

Flat against the wall by the door, he felt the reverberation as Lupin closed it and then watched him depart down the corridor. He listened, rapt, to the thrumming in his chest as the echoes of Lupin's footsteps faded. He was aware his back was damp – he was leaning against the dungeon wall but couldn't be certain whether it was simply the lake water leaching through.

It took several moments to persuade his feet to return him down the familiar route to Gryffindor Tower. It was only then he dared hear his own voice whisper to the empty common room: 'My dad's alive.'

-x-

The night was excruciating. It had been later than he'd thought when he'd got back to the dormitory; Ron was already in bed, and he'd nearly tripped over his muddy Quidditch kit. He couldn't rouse him enough to persuade him to the privacy of the common room, and Harry didn't get a wink of sleep. But he must have nodded off before morning came, because the sun was shining on Ron's empty pillow, and Harry faced another tortuous wait as he hurried down to the Great Hall.

He found him down the far end of the Gryffindor table. It was busy; he took the seat next to Hermione, but she was deep in conversation with Parvati Patil. Ron, opposite, was listening to Dean while chomping toast. Harry didn't feel like eating, though he poured a goblet of pumpkin juice and found he was thirstier than he thought.

Parvati was getting up to leave, and Hermione turned to him. She paused – his sleepless night must have been showing. 'Are you all right?' she said.

'We need to talk,' he whispered.

She looked solemn, and glanced at Ron, who was busily obeying the demands of his appetite after last night's Quidditch practice. 'Is this about yesterday?' she asked, leaning toward him so the others wouldn't hear. 'What did you find out?'

'Not here.'

She watched as he poured himself another pumpkin juice. 'Aren't you eating anything?'

'I'm not hungry.'

'So, Harry – how'd it go?'

He looked up from his goblet at Dean – Ron, chewing less eagerly, had also turned his attention his way. 'What?' said Harry distractedly, his thoughts on getting Ron and Hermione somewhere quiet so he could share his news.

'Last night – did you find anything out about Snape—' Dean glanced up at the High Table, but Snape wasn't there. 'Is he leaving, or what?'

'Yeah,' put in Seamus, 'I heard Lupin's here, isn't he?'

'Harry said Dumbledore called Lupin here yesterday,' said Dean, sounding pleased to know more about it than Seamus. 'He saw him arrive – and he heard Dumbledore ask him to help talk Snape out of leaving, didn't you?'

It felt like a hundred years ago to Harry. 'Yeah – I mean – Lupin's not staying, he's just visiting for the Wolfsbane Potion – and Snape's not leaving.'

'Ah, for —' Ron swallowed the last of his breakfast. 'Well, that's just great, isn't it?' He sat back and fingered his left arm through his robes. Harry knew what was coming next. Dean also seemed to know. He was already looking down at his plate to hide the smirk. 'Dumbledore's got a lot to answer for. So's Lupin.' Ron shook his head, then finally pushed up his sleeve and announced, 'Still there.' Dean focused on slowly refilling his goblet.

'It's just a freckle, Ron,' said Hermione with the same sort of patience Harry often heard from Molly Weasley when talking to one of her children.

Ron's face went red, as though his very freckles were outraged by her dismissal. 'It's not just a freckle. It's a bruise, anyone can see that. All right – maybe it's gone down a bit since the git grabbed me. But the evidence is there. Can't deny what he did.'

'No, I'm not. Of course I'm not. He hasn't been nice to anyone lately—' Dean sent her a look of incredulity, perhaps wondering when Snape had ever been nice. 'Look,' she pressed on, 'maybe Professor Snape will be back to normal now after talking to Lupin, about –' she glanced at Harry, obviously curious about his desire to talk privately '– whatever.'

'Normal? Fantastic,' said Ron. 'Looking forward to that.'

Hermione gave him a look. 'He's been worse to Harry – worse than usual. Gryffindor's never lost so many points so early in the year before. It's been awful for everyone. So let's hope things change,' she said, turning to Harry.

He hoped so too. He couldn't bear the thought of the rest of the year's Potions classes being just the same – Snape zoning in on him right from the start, bursts of anger over the smallest of mistakes – made worse of course because of his efforts to get it right and avoid these clashes – followed by extended tirades about how much he resembled his big-headed, lazy, foolhardy father. Ron had lost his temper last week and earned a swift exit for his mumbled 'git'.

But it would be so much harder now he knew that … that his dad was alive.

His head felt light just thinking it. He needed to find a quiet moment so he could tell Ron and Hermione. But the table was already clearing, showing a line of miserable faces as the bad news sank in: the rumours about Snape leaving Hogwarts had finally been quashed.

'Well,' said Hermione when they were at last outside. Harry led them to a nearby tree, the early November wind whipping about their robes as they walked. 'I think it's probably a good thing Professor Snape's not leaving – not with You-Know-Who back.'

'Says you,' said Ron, slumping against the wide trunk of the tree as it threw down a brown leaf onto the mottled grass at their feet.

'My dad's alive.'

They both turned to him.

'I heard Snape say it,' he said to their blank faces, 'inside his office – to Lupin.'

'You were inside Snape's office?' Ron straightened up, and Harry felt somewhat annoyed that it was this that had got his attention. 'That's brilliant. How'd you manage it?'

'But – your dad?' Hermione was studying him. 'How—?'

'I don't know how. I just know it's true.' His mind went back to last night. 'D'you think they've known all along?'

'But – wait – what happened, what did Snape say exactly?'

He heard Snape's mocking words again. 'He said, "Oh, Potter, your father James didn't really die after all".' He couldn't help repeating them with something of Snape's unique bitterness.

'I don't get it,' said Ron. 'He saw you?'

'He was pretending I was there, taunting me – he kept saying to Lupin over and over that he'd never tell me, making him promise not to as well. What's Snape got to do with this anyway?'

'But, Harry,' said Hermione, showing none of Harry's desperation, only a quiet concern. 'How can your dad really be alive after all this time?' Her voice lowered to a hush. 'They found his body.'

'I don't know. All I know is Dumbledore and Lupin swore they'd never tell anyone – including me. And everyone else thinks he's dead.' Since last night, Harry had been floating on the excitement of all the possibilities that had opened themselves up to him. But now that excitement gave way to worry, and anger – why had this been kept from him?

'It just seems so – unlikely.'

'I heard him say it! They're keeping it from everyone!'

'But why would they—?'

'I don't know! Why don't you ask them!'

'So where is he, then?' asked Ron. 'Your dad? If he is alive,' he added at Hermione's sharp look.

Harry thought through what he'd heard. But there was nothing. 'They didn't say anything. But Snape's got a hold over everyone. He knows something.' He felt a chill of worry. 'If Snape's at the centre of this somehow … he hates him, he can't stand the thought of him being alive…' His mind spun; he had never felt so frustrated.

'Harry, please, we have to think about this rationally,' said Hermione, and Harry could hardly understand how she could stay so calm. 'What about what you saw this summer? When You-Know-Who… The Priori Incantatem?'

'Oh, that. Well, there's got to be some other explanation for that, hasn't there?'

She didn't offer any. 'What happened to listening at Snape's door?' she said.

'Good thing I didn't, or I might never have heard.'

'But you were taking a risk… What on earth made you go inside?'

'I dunno, I just did.' He was getting nowhere with these questions. 'But I'm glad, or I wouldn't have found out my dad's alive.' He thought he would never tire of saying those three words, and the thrill they sent; it cut through his anger, and he kneaded his head around his prickling scar. 'Aren't you? Aren't you glad I did?'

'We are,' Hermione said, and she made an effort, her face opening a little to reflect some of his joy. 'Of course we are. But – if… what Snape said is true—'

'It is! He said it!'

'All right, but… then we need to find out where he is, don't we?'

'Maybe your mum's alive too?' said Ron, his eyes wide with some of Harry's hope.

But Harry had already considered this wonderful possibility last night as he had thought of what he had seen in the Mirror of Erised. 'It's her blood magic protects me,' he said, and he was cast down all over again, descending with the loss of something he had never had. 'She must have died. It was her death that saved me from Voldemort's Killing Curse.' With the promise that one half of his greatest desire would soon be fulfilled, he had naturally wanted the other half with it – but he had only succeeded in earning a sharp kick of guilt at his unreasonable greed.

They stood in silence. Classes would be starting soon, but Harry was in no hurry to go back inside; the twisting breeze matched his restless thoughts. 'D'you think,' said Hermione after a moment, 'it's something – something to do with You-Know-Who?'

'How d'you mean?'

'Well, I was just thinking… the timing… with You-Know-Who coming back and the Order of the Phoenix reforming, now Snape saying this—'

'You think Voldemort's got him?'

'What?'

She was shocked, but it made perfect sense to Harry. Why else would Snape know about this? 'Snape said he wished Dumbledore hadn't told him something. Maybe Dumbledore found something out and then forced the truth out of him. They made it look like he'd died – that's got to be it. Snape and Voldemort. And then… What if he was tortured like Neville's parents? What if he's in St Mungo's and no one knows who he is? What if he's in Azkaban – Snape'd love to put him there, like Sirius. Or some Death Eaters are holding him—?'

'Harry!' cried Hermione desperately. 'Even if – even if Snape knew about it, it doesn't mean he's in trouble.'

'If my dad was all right, he'd have tried to contact me, wouldn't he?'

'Well… but if Dumbledore knows, and Lupin, then they wouldn't let anything bad happen to him.'

'But they only know now. Snape's just told them now, because Dumbledore made him. And why won't Snape let them tell anyone else? Why doesn't he want me to know? Don't you see? Snape's got everyone wrapped round his little finger.' An image of the greasy-haired professor sneering with satisfaction at having kept the truth from him swam into his mind. He had imagined him drowning in his own cauldron often enough, but right now he would give all his gold from Gringotts to see it for real. 'And Dumbledore trusts him!' He clenched his teeth. 'I hate him.'

'Yeah, me and you both, mate,' said Ron. 'You've got to see someone about this. Dumbledore or Lupin. Never mind Snape – they've got to tell you – he's your dad.'

Harry shook his head. 'They won't, I know it. Snape's convinced them all my dad'll be safe as long as no one else knows the truth.' He had a terrifying thought. 'Maybe they're scared of what Snape'll do to him.'

'Look, Ron's right,' said Hermione. 'You've got to find out what's really going on. It's going to eat you alive if you don't. I'm sure your dad's okay – but you'll just carry on thinking the worst unless you find out.'

'But how?' He lifted his shoulders in defeat. 'And what if something really bad happens to him when they find out I know?' He looked to the castle and shook his head. 'If he hasn't tried to contact me in all these years, then what can I do? I can't risk doing any more sneaking or searching around. I might just end up getting him into even more trouble.'

Ron and Hermione traded looks of anxiety as they stood in contemplative silence. Harry's powerlessness to help his father left him with a hollow feeling deep inside, as though something had been gouged out from his belly. He wondered if this was what it felt like to worry for a parent, to grieve for a parent. His head was still light from lack of proper sleep, thoughts teeming freely, refusing to obey his weary need to know the truth. All the increased taunting from Snape over the past weeks made sense now – he must have been furious when Dumbledore had forced him to come clean on what he knew about James.

But Harry wasn't going to stand by and do nothing – he swore he would find a way to make sure his father was safe; he would not allow Snape to continue keeping the truth from him. Whatever it took.

-x-

It was the first time Snape had been in Dumbledore's office since discovering in this room what had happened to James Potter. He glanced at the cabinet where – was it just sixteen days ago? It felt longer – Dumbledore had brought out the two glass jars containing samples of magic, one of which was his. Except that it wasn't.

'Did you see Remus?'

Snape turned to Dumbledore, sat at his desk, eyes moving over a parchment from a pile in front of him.

'Oh, yes, Dumbledore. Indeed.'

'Excellent. It's kind of you to agree to make the Wolfsbane Potion again for a while. I hope he'll suffer less.'

Snape set his mouth; he was in no mood to humour him in his schemes. What had the meddling Headmaster imagined, bringing the werewolf here? He could not think of James Potter and Remus Lupin together without seeing Lupin's turned head on the perimeters of Black and Potter's attacks. It was an association fixed in eternity. The werewolf's presence only served to remind him of why he poured hatred on his memories of James Potter, the man who had played with lives to massage his already overblown ego. With jaw fixed, he watched Dumbledore set aside the raft of parchments.

'And have you had the chance to reconsider your position here?'

Snape scowled freely. Dumbledore knew he had not been serious about leaving the school. He had wanted to be rid once and for all of the boy who had his father's face... But he had not been thinking straight. Perhaps he should have demanded the Defence Against the Dark Arts job in return for staying. 'As you well know, I cannot leave with the Dark Lord now risen again. He expects me to remain here as spy.'

'Well, of course. Good.'

Snape scanned the portraits on the walls – most were in some other picture or napping in their painted chairs, just as they had been two weeks ago. It was extraordinary how much they managed to sleep through in this office. It had been just beneath the empty frame of Phineas Nigellus that Dumbledore had shown him his little test. Fawkes on his nearby perch had flapped his wings, disturbing the dusty air, as Dumbledore had first set down onto the cabinet the results he had gleaned from the secret test he'd done earlier. Done on Snape's own magic – what he had thought was his own.

'I expect you called me here for a reason?' said Snape, turning back to Dumbledore, who had put out a hand towards an open box of sherbet lemons. 'Perhaps another revelation – have you discovered some other piece of me that is not mine?'

Dumbledore's fingers glided higher to the lid and brought it closed. He folded his hands and gave him his attention. 'I'm sure the rest of you is firmly yours, Severus. No, I do wish to ask something of you. But I will get to that. First, you – how are you feeling?'

'I have never felt better. There is nothing quite like discovering one's soul is not one's own but that of a person one loathed.'

Dumbledore gave a little cough, to Snape's satisfaction. 'You know it will take time.' But it seemed the topic of Snape's welfare was a brief one. 'Yes,' said Dumbledore with sudden gravity, signalling a return to the previous subject, 'we must be vigilant with Lord Voldemort among us again.'

'Vigilant – yes. We must avoid occurrences like last year with the Mad-Eye Moody that wasn't, mustn't we? Such as by taking samples of the staff's magic for the school records?'

Dumbledore refused to look away. 'You know I had to be sure. Would you have wanted to go through the test without my being certain of the result first?'

'I thought the Death Eater who'd witnessed it all had confirmed it under Veritaserum?'

'Yes, he did.' Dumbledore sighed and removed his glasses. He gazed at them for a moment, before putting them back on. 'I am sorry for misleading you on the purpose of the sample. But not for informing you of the truth.'

'Really? I still don't see what good it does, my knowing. Nor, indeed, what difference any of this makes.'

'It is the truth – and I find the truth has a habit of coming out sooner or later – usually under worse circumstances.'

'Do you still have it in there? Your little test?'

Dumbledore's silence said it all.

'Maybe in case I have doubts? Then why not put our minds to rest and run it again?'

'There is no need…'

'Oh, but I insist.' Snape rose so he no longer had to see the disinterest in Dumbledore's surprise. He strode to the cabinet and opened it without waiting to hear his reply. There they still were, at the edge of the second shelf. 'What do you say, Dumbledore,' he said, turning with his hand on the door, 'fourth time lucky?'

Silence for a moment. Then: 'Very well,' and he moved his chair back, his face stolid, and beneath it Snape knew he was finally taking him seriously. 'If you are certain you want it. But after this – no more.'

It was a simple thing, taking a sample from a wizard's magical core, though Snape had never witnessed it being done before last month. There was little use for it – unlike containing someone's memory in the hopes of obtaining valuable information, having a sample of someone's magic merely meant one had his magical signature on hand, should it be needed. Such as for a test.

Now he had Dumbledore's full attention, Snape felt little enthusiasm for repeating this thing. But Dumbledore was taking out one of the bottles, leaving behind the other, which bore his name on the glass – an irony indeed – and setting it on top of the cabinet just as he had done two weeks ago. And just as then the portrait above that normally contained Phineas Nigellus looked down vacantly. Snape got out his wand and pointed it a foot above the bottle.

Dumbledore checked Snape was ready, and touched the stopper. As soon as it was removed, the magic crept out, its yellowish hue, faint from being spread out greedily in the bottle – little was left of it now since their previous three tests, and Dumbledore's secret one before that – deepened in colour as it conspired at the neck.

'Subcriptio.' From Snape's wand issued a matching gold, its thin strand breaking free. It floated forward and down, inching closer. It seemed to take an age, then as now.

In days past it might have curled around a roll of parchment – a more reliable seal for important documents than the Muggles' use of candle wax – or leave a stain of gold – the family gold – beneath an inked signature.

But today the strands found no paper targets. Instead, as though sensing a fellow wanderer, their movements changed, at first subtly.

Unlike strands would repel, as though nobles of different houses racing past one another in joust, sparks flying where violent contact was made.

But not today. Today they recognised a member of the same paternal house – the Potter house. They greeted with strong embraces. The threads of magic wound around one another as they passed, weaving together with increasing speed, with an eagerness that was almost obscene at one another's touch, curving upward under the combined momentum, until they were a single golden cord rising to the ceiling victorious. The Potter line, united.

Snape replaced his wand and let Dumbledore deal with clearing it all away. He retook his seat and waited. A moment later, after the soft thud of the cabinet door, Dumbledore was back behind his desk. 'So, you said you wanted to ask something of me?'

Dumbledore did not answer straight away. 'Yes,' he said, seeming to consider the question. 'The Ministry is still denying Lord Voldemort's return.'

'What more is there to be done?'

'I'm sure something will come up. But there's been something…' He paused, then looked across at a table where a wind-up clock appeared to have stopped and several silver instruments whirred softly. 'I'm late for my meeting with Fudge.'

'He's been expecting you?'

'No.' Dumbledore smiled and rose. 'Walk with me downstairs?' Snape followed as he retrieved his travelling cloak from the stand. When they were in the corridor, moving out of sight of the gargoyle, he said, 'Harry's scar has recently been hurting him more. Since Voldemort's return, in fact.'

'Really?' For Potter there was now the threat of losing all the attention he had carefully built up over the years. If the Dark Lord were revealed, all eyes would move to him, and Potter would find no one to pay heed to his sulking.

'It's more than coincidence. There is something behind it … a change in him. I fear Voldemort has already begun seeking to influence him through their link.'

'The Dark Lord has better things to do with his time.'

'Perhaps. But perhaps he doesn't quite share your certainty.' They came to a stop at the head of the marble staircase. The entrance hall below was empty, and silent but for the sound of distant footsteps as someone moved from one room to another. Most of the students were back in their respective common rooms after dinner. Dumbledore turned to him. 'Which is why I wish you to teach Harry Occlumency.'

'What? Me?'

'Perhaps you could begin as soon as possible?'

'Yes, why not now? I'm sure I'd like to see what pudding he had tonight. On the floor as well as in his head.' He hunted through Dumbledore's framed expression for the sign he was merely being played with. 'I see the value in it. That is, if Potter has the capacity. Which he won't, given his mediocrity in everything else. But – if you think it wise to try it – wouldn't the boy learn better with you as his instructor?'

'I've noticed in him certain feelings of aggression toward me, something within him seeking an opportunity to attack.'

Snape could hardly blame the boy for that. He had felt much the same since Dumbledore had told him the fate of Potter senior.

'I fear Voldemort is behind it. It means there is little chance of him learning anything useful from me. Which is why you would be the better teacher. In addition to your excellent skills in the art, of course.'

Snape ignored the strategically placed praise and the amiable smile accompanying it, his mind instead working in search of a reason to get out of teaching the Potter brat. 'Dumbledore. With what has recently transpired … Potter's father … it would create difficulties – surely you see that?'

'Harry is not James.'

There were no words for this. Snape could feel a headache coming on – but better that intractable heat than the cool arrangement of thoughts that would spell out the inference that followed from Dumbledore's simple statement.

'Good,' Dumbledore said before Snape had time to think further. 'So do please inform the boy when his first lesson will be.' He turned and seemed to spring down the stairs as though he'd just remembered where he'd put a favourite pair of socks, cheerily greeting a passing student. Snape seethed at the girl, and wondered whether it would not be preferable to reconsider his position at Hogwarts, and risk the Dark Lord's wrath after all.