When he arrived at the History of Magic classroom the following Thursday just after 8:00 PM, Remus found Harry already there, waiting for him nervously. He looked relieved when Remus explained that they would be practicing on a Boggart instead of a real, live Dementor. When Remus drew his wand, Harry hesitantly following suit.

"The spell I am going to try to teach you is highly advanced magic, Harry," he admonished. "Well beyond Ordinary Wizarding Level. It is called the Patronus Charm."

Harry nodded. "How does it work?" He eyed the packing case containing the Boggart nervously.

"Well," he said slowly, trying to find the best words to explain something as complicated as this spell to an impatient thirteen-year-old, "when it works correctly, it conjures up a Patronus, which is a kind of Anti-Dementor - a guardian which acts as a shield between you and the Dementor."

He hesitated. That was, of course, the basic function of the Patronus. It was much more complicated than that, and had many other uses than repelling Dementors, but for now he wanted to explain the immediately useful aspects of it to Harry in the simplest terms possible. The better the boy understood what he was trying to achieve, the greater his chances of success.

"The Patronus is a kind of positive force," he continued. "A projection of the very things that the Dementor feeds upon - hope, happiness, the desire to survive."

All the things which had been taken from Remus without a Dementor coming within miles of him. Sometimes he thought he might as well have ended up in Azkaban himself.

"But it cannot feel despair, as real humans can," he continued, wrapping the cloak of his professorship tightly around him to ward off the pain of the subject matter, "so the Dementors can't hurt it. But I must warn you, Harry, that the Charm might be too advanced for you. Many qualified wizards have difficulty with it."

A look of determination entered Harry's eyes. How like James he looks! James, who had never let a spell defeat him, once he had put his mind to learning it. From that look alone, Remus knew that it would only be a matter of time before Harry was able to conjure a creditable Patronus.

"What does a Patronus look like?" Harry asked.

Harry had been unconscious on the train when Remus had conjured his own Patronus, but even that would have told the boy little enough about them. Remus had once been able to conjure a very impressive Patronus, which took the form of a large and familiar-looking dog. But since that terrible Halloween night, he had been unable to produce much more than an indistinct silvery cloud. To conjure a Patronus, one needed a happy thought, and on that night all of Remus's happiness had been ripped away from him, and what memories he still carried had been tainted forever.

"Each one is unique to the wizard who conjures it," he told Harry.

He was curious to see what Harry's Patronus would look like. No doubt he would find out before long. He wished he could instill the confidence he felt in Harry himself.

"And how do you conjure it?" Harry asked.

"With an incantation," Remus told him, "which will work only if you are concentrating, with all your might, on a single, very happy memory."

He hoped Harry would have a happy enough memory available to him. Parents dead, raised by Muggles who disliked him and feared magic, he had not had much opportunity for good to happen to him until his arrival at Hogwarts less than three years ago. Remus desperately hoped that something extremely good had happened to Harry at some point in his life; the love of his family, which Remus himself had witnessed and been party to, was beyond the grasp of his memory.

Harry looked as though he was thinking very hard. The longer he thought, the sadder it made Remus to watch him.

Think of something, Harry, he begged silently, or I fear that what's left of my heart will break for you. Lily and James's son deserves so much better.

At last, Harry nodded, a doubtful but once again determined expression on his face.

"Right," he said, looking to Remus for further instruction.

"The incantation is this -" he cleared his throat, "Expecto patronum!"

"Expecto patronum," Harry muttered, memorising the words. "Expecto patronum."

"Concentrating hard on your happy memory?" Remus reminded him.

"Oh - Yeah -" Harry replied, becoming suddenly flustered and garbling the mumbled spell.

That was the trick to it, really. In theory, it was easy enough to point one's wand and say some words, but a spell like this one required a high degree of mental discipline. One had to remember the words, remember the happy thought, believe in the Patronus, and all while facing at least one Dementor. No surprise if it was a difficult spell to master.

Harry kept trying the words over and over, looking hopefully at his wand. Suddenly, what looked like a tiny curl of silver smoke drifted from the end, quickly vanishing into the air.

"Did you see that? Something happened!"

The look of surprised joy on Harry's face made Remus smile. He had not conjured more than a wisp himself before he was sixteen.

"Very good," he told Harry. "Right then - ready to try it on a Dementor?"

"Yes," Harry said, somewhat defiantly.

Looking very pale, he moved to the centre of the classroom and squarely faced the packing case that contained the Boggart, feet planted, wand at the ready.

Remus looked at the boy for a moment. The expression on his face was unreadable. Well, there was only one way to find out if he was really ready. Standing behind the desk, opposite Harry, he put both hands on the lid of the packing case and pulled.

The Dementor which rose from the box looked very real. Remus backed up until he met the wall, holding the lid of the box to his chest like a shield. His eyes rose with the Dementor facing Harry. Immediately, all the heat was gone from the classroom. The lights guttered and extinguished themselves.

Remus tore his eyes from the cold thing to see Harry frantically waving his wand and shouting "Expecto patronum!" over and over again. His eyes were visibly losing focus, and each time he spoke the incantation, his voice sounded a little weaker. He took a step back, and then another, looking more and more frightened, more and more lost. His eyes rolled back in his head and he dropped.

Remus vaulted over the desk, putting himself between the Boggart and Harry. The Dementor turned its head toward him, and suddenly Sirius was grinning at him, holding out his arms.

"Riddikulus! Get back in your sodding box!" he shouted. Please, God, don't let Harry see this!

He forced the Boggart back into the packing case, then waved his wand vaguely at the lamps to re-light them as he turned his attention to Harry.

The boy was sprawled on the floor, perfectly still and white as a sheet, sweat standing out on his face.

"Harry! Harry!" Remus called, shaking him. He'll be all right. He'll be all right, he kept telling himself. Arse! Why did I let him do this?!

Harry's eyes popped open, darting around the room until they fixed on Remus's face leaning over him. Remus could almost see the boy's memory returning.

"Sorry," Harry muttered, sitting up much more quickly than Remus would have liked and groping for the edge of a desk to pull himself to his feet.

"Are you all right?" Remus asked in a worried tone, fumbling through the pockets of his robes for chocolate. His fingers brushed the little wooden dog, and he drew his hand out of that pocket quickly to search another.

"Yes." Harry leaned heavily against the desk, still gripping it with both hands. Remus really wished he would sit back down.

"Here," he said, handing the boy a chocolate frog. "Eat this before -"

He had been planning to send the boy back to Gryffindor tower, to the company of his friends and the warmth of his bed, but when he met Harry's eyes, he saw the look of determination back in place and the colour returning to his cheeks.

"- before we try again," he finished. Then added, "I didn't expect you to do it first time. In fact, I would have been astounded if you had."

That was true enough. He did not really expect Harry to get much of a result while facing the Boggart tonight.

"It's getting worse," said Harry through a mouthful of chocolate. "I could hear her louder that time - and him - Voldemort -"

Remus felt all the blood drain from his face, as if he himself could hear Lily screaming. It would be too much for him to bear. How could he expect her son to face it again?

I was wrong, he decided. I should have sent him to his bed after all.

"Harry," he began, "if you don't want to continue, I will more than understand -"

"I do!" declared Harry, his cheeks burning, the fire back in his eyes. He swallowed the rest of his chocolate frog quickly. "I've got to," he continued, looking at his teacher with pleading eyes. "What if the Dementors turn up at our match against Ravenclaw? I can't afford to fall off again. If we lose this game, we've lost the Quidditch Cup!"

Of course that was what Harry cared about. Remus mentally kicked himself for forgetting that Harry was only thirteen - that his priorities were not those of an adult. The terror of the Dementors, his parents' murder, the fact that Sirius was after him - all of these things were too abstract for Harry to properly comprehend. What was real to him was the prestige of winning the Quidditch Cup or the humiliation of losing it.

It wasn't Harry's fault. Remus remembered being thirteen, when full moons were an annoyance that separated him from his friends, rather than a horror that brought him face to face with the vicious monster living inside him. But that did not make it any less important for Harry to be able to drive off the Dementors.

"All right then," he said at last. "You might want to select another memory, a happy memory, I mean," he said quickly, "to concentrate on - that one doesn't seem to have been strong enough."

He watched in sympathy again as Harry wracked his brains for another, happier memory. At last, he smiled, and Remus sighed with relief. Harry was not without happy events in his past. Knowing that made Remus feel slightly better. Not everything good about the Marauders had died that night, and the proof stood before him, looking to him with trust, if not with love.

Harry squared his shoulders and faced the packing case again.

"Ready?" Remus asked, hands on the box lid.

Harry nodded. "Ready," he said, aiming his wand and staring hard at the box.

"Go!" he heard himself say, and off came the lid.

Again, the room went cold and dark almost at once. Harry yelled the incantation over and over, but the Dementor-Boggart kept on gliding toward him, and once again Remus watched the boy's eyes lose focus and his knees buckle.

Once more Remus set himself between Harry and the Boggart, which now looked like a wounded Sirius, begging for his help. He closed his eyes, picturing something - anything - that was not Sirius Black, and shouted "Riddikulus!" Opening his eyes, he saw the full moon with Sirius's face grinning down from it.

Why not? he thought with a humourless smile. You both torment me.

He brought the lid down on the glowing Boggart.

Harry looked even worse this time; not just pale, but positively gray. Though he was unconscious, there were tears flowing freely down his cheeks, mingling with the sweat. Remus could only imagine what the boy had seen and heard, but imagining was enough. His own eyes stung. He wished he could take Harry in his arms and comfort him until all the horrible memories went away, but he knew that it was hardly a gesture that a thirteen-year-old boy would appreciate, especially from a stuffy professor. He settled for taking Harry's hand in his own and patting it.

"Harry?" he inquired, tentatively at first. When there was no response, he said a little louder, "Harry?" Still nothing.

The tears still flowing down his cheeks upset Remus. He wanted to get Harry awake and get some chocolate into him as quickly as possible. He smoothed the sweat-soaked hair from his forehead, gently tracing the lightning bolt scar with a finger.

I suppose that night had to leave a mark somewhere, he thought, wondering anew at the miracle of this boy's survival.

Harry still showed no sign of coming around. His eyelids twitched as if he were dreaming, and from the set of his mouth, it was not a pleasant dream. Remus shook him, calling his name again and still got no response.

"Come on, Harry," he muttered. "Don't do this to me."

At last, Remus sighed and drew his wand. It was not good to force the body's natural state with wand magic. Healing was best done with potions and infusions of herbs. He tapped Harry's forehead with his wand.

"Ennervate."

Harry's entire body twitched, and his eyelids began to flutter. Remus put his wand away.

"Harry," he urged the boy gently, "Harry, wake up -"

Harry's eyes opened. He lay on the floor, staring up at the ceiling, making no attempt to move, and clearly having no understanding of why he was there in the first place.

I should have let him wake up on his own, Remus thought angrily to himself. It's jarring to be woken by magic. But dammit, he scared me!

At last, Harry slowly turned his head to look up into the face of his very worried teacher.

"I heard my dad," he said in a groggy voice. "That's the first time I've ever heard him - he tried to take on Voldemort himself, to give my mum time to run for it -"

Harry sat up to wipe his face on his robes, but Remus barely noticed. He stared over Harry's shoulder, through the window, out into the darkness of the January night, not seeing it.

Isn't that just like James? he thought. Always so full of reckless bravado, and nothing in this world more important to him than Lily and Harry. She always said his overconfidence would be the death of him.

He looked at Harry, who appeared to be fiddling with an already-tied shoelace.

He really does remember, doesn't he? he thought with wonder. He's not just imagining this stuff. He never knew James - not like I did - but he seems to know exactly how he'd act.

With no witnesses to their deaths save Harry, all Remus had ever known was that they had died. But now the horror of the scene was becoming clearer and clearer in his mind. James barring the door, wand in his hand, shouting for Lily to go. Lily reaching for Harry in his crib, looking to James in terror. Both of them knowing that they had been betrayed, and by whom, and that they were going to die.

But not without a fight. Not them. Never without a fight.

Their courage had somehow saved their son, and brought about the downfall of Voldemort. And now their son sat at Remus's feet, pretending he was not fighting back tears, because his only memory of his parents was at the moment of their deaths, and because they had both died to save him.

Remus felt a deep kinship with this boy. Who else had lost so much on the night which had caused the rest of the Wizarding world to rejoice? If he had been alone, Remus would have wept as well, out of pity. But he couldn't let Harry see that.

"You heard James?" he asked instead, knowing his voice sounded choked.

"Yeah .-" Harry finally looked up. His eyes were red. "Why - you didn't know my dad, did you?" he asked suddenly.

Remus was flustered by the unexpected directness of the question. "I - I did, as a matter of fact. We were friends at Hogwarts." He really did not feel like he could handle discussing Lily and James just at the moment, so he changed the subject. "Listen, Harry - perhaps we should leave it here for tonight. This charm is ridiculously advanced - I shouldn't have suggested putting you through this -" Or me, for that matter.

"No!" said Harry, struggling to his feet once more. "I'll have one more go! I'm not thinking of happy enough things, that's what it is - hang on -"

His brow furrowed and he pressed his lips together, tapping his fingers on the desk. At last, he took a deep breath, let it out, and faced the packing crate once more.

"Ready?" Remus asked from behind the desk, wishing very much that he had followed his first impulse to send the boy to bed with a large supply of chocolate. "Concentrating hard? All right - go!"

Once again, the Dementor rose between them, and once again Harry raised his wand, looking pale but determined. His hair was standing on end just like James's always had when he was agitated.

"EXPECTO PATRONUM! EXPECTO PATRONUM! EXPECTO PATRONUM!" Harry bellowed over and over again, shaking his wand as the lights flickered and died and all heat left the room.

The Dementor advanced, but Harry stood his ground.

Concentrate, Remus thought hard at him. You can do this, Harry. I know it!

Harry's eyes got bigger and bigger as the Dementor approached, but he never stopped shouting or waving his wand, and he never took a step backwards. The Dementor stopped.

"EXPECTO PATRONUM!" Harry shouted one last time, and a huge, silvery cloud burst from the end of his wand. It hung in the air between Harry and the Dementor, and the three of them - Harry, Remus, and the Boggart - stared dumbly at it for a second.

Then Remus saw Harry begin to sway, and leapt forward, shouting, "Riddikulus!"

The Boggart once again turned into a tiny full moon emblazoned with Sirius's face laughing cruelly at him, but he was fairly sure Harry was too far away to see as he forced it back into the case.

When he turned to face Harry again, the cloudy Patronus had vanished.

"Excellent!" he said in heartfelt tones. He strode across the room and sat next to the exhausted boy. "Excellent, Harry. That was definitely a start."

He suppressed a strong urge to give Harry a hug. Lily and James would have been so proud! He was proud!

"Can we have another go?" begged Harry. "Just one more go?"

"Not now," he said with a smile, rummaging through the pockets of his robes again. "You've had enough for one night. Here -" He gave Harry a bar of Honeydukes' best chocolate which he had been saving for just this occasion, though admittedly he had thought it would be weeks away. "Eat the lot," he admonished, "or Madam Pomfrey will be after my blood."

Harry looked as though chocolate was a poor substitute for another chance to conjure a Patronus, so Remus added, "Same time next week?"

"Okay," Harry replied, seeming satisfied with that

He unwrapped the chocolate and began to nibble at a corner of it as Remus moved around the room extinguishing the lights.

"Professor Lupin?" he said after a moment. "If you knew my dad, you must have known Sirius Black as well."

He stopped dead, facing the wall, very glad that Harry could not see the expression on his face. He hoped that in the now-dim light, Harry had not seen the stiffening of his shoulders at the mention of that name. He turned, unconsciously glaring at the boy.

"What gives you that idea?" he asked rather more sharply than he intended.

Harry looked alarmed at his teacher's sudden change in demeanor. "Nothing - I mean, I just knew they were friends at Hogwarts, too -"

The tension left his body. Obviously Harry was not drawing any of the same suspicions or conclusions as the adults at the school were. But it was still difficult to talk about Sirius, especially with Harry.

"Yes I knew him. Or I thought I did." He suddenly felt very tired. "You'd better get off, Harry. It's getting late."

Harry gave him a worried look before hurrying back to Gryffindor tower. He listened until he could no longer hear the boy's footsteps in the corridor before gathering up the Boggart's box and headed back to his rooms, hoping vainly for dreamless sleep tonight.