Harry's classroom is completely empty, quiet except for a rattle coming from a cupboard in the back. Harry closes the door behind them. The last thing they need is an audience for this.

"Is that it?" Jamie asks, eyeing the cupboard warily. "The Boggart?"

"Yes. McGonagall sent it over, apparently it got into a cupboard in the Headmistress's office somehow," Harry says.

Jamie nods, and takes a deep breath. He's holding his wand tightly, tight enough that his knuckles have gone pale with the force of it.

Harry wants to ask him what he's expecting to see. He doesn't know if he wants to know or not. If it's making Jamie this upset, then it's got to be something big, something truly terrifying. Instead of asking him, he says, "So. What do you know about Boggarts?"

"They take the form of the thing you're the most scared of," Jamie says. "And they rattle around in cupboards and things. I remember the one that you and Mum found in the Burrow last year. Proper little shits, really."

"Language," Harry says, but there's no bite in his words. "Well, you're right. And you get rid of them by laughing at them. It's not real, see. You have to remember that. No matter what it looks like, it's not real. So you look at it, and then you find a way to change it into something worth laughing at. I reckon you'll be good at that," he adds mildly.

"Okay," Jamie says. He seems to steel himself visibly.

Harry can't help himself then. "What do you think it'll be?" he asks.

Jamie looks at Harry. "I don't want to say," he says, setting his jaw in a show of stubbornness. "Not until I know if I'm right or not. Just… promise me you'll be here the whole time?"

"I promise," Harry says without hesitation. He doesn't have to think about it, doesn't need any other details.

"Okay. Alright. Then… I'm ready," Jamie says.

Harry glances at Jamie. He looks as ready as he'll ever be, which is why Harry points his wand at the cupboard in the back to unlock it.

The door swings open.

At first, there's nothing, nothing at all, and then, suddenly—

Everything gets colder.

They're indoors, but the entire room seems to get darker. Foggy, almost.

And then, all of a sudden, Harry knows what's going to emerge from the cupboard before it does.

A tall, cloaked figure emerges, floating off the ground, hooded and covered from head to toe. A Dementor, undeniably, unmistakeably so. Harry knows it's a Boggart, logically, but he can't stop the shiver that runs down his spine. A claw-like hand emerges from beneath the cloak, and the Dementor – the Boggart – takes in a deep, rattling breath.

Harry thinks it's his Boggart at first, but when he turns to look at Jamie, he's pale and shaking all over. Harry can't say that he blames him. He feels much the same. He can't explain how, but he just knows that this is Jamie's Boggart, and not his. "I'm here, Jamie," he promises.

"Expecto Patronum," Jamie chokes out. A silver mist emerges from his wand, not quite corporeal.

"No—Jamie, it's not real," Harry says. He has to force the words out. "It's not a Dementor. Remember that. It can't hurt you, not if you laugh at it."

Jamie screws his eyes shut. "I—Dad," he says, weakly.

"It's not real," Harry repeats.

Jamie opens his eyes and focuses on the Boggart. "R-riddikulus," he says. Nothing happens. The Boggart floats a bit closer, and Jamie shudders.

"Try again," Harry says.

"Riddikulus," Jamie repeats. His voice is stronger this time.

The Boggart trips over its cloak, and then falls to the ground, hitting the ground head-first with a splat that is very, very satisfying.

A sudden, genuine laugh escapes Harry. After a second, Jamie joins him, leaning into Harry's side as he laughs. The cold starts to recede, and then Harry can't seem to stop laughing. His ribs ache with the force of it, and when he looks up, the Boggart is unsure, flickering between a Dementor, a clown, and – of all things – a snake on rollerblades. He directs it back into the cupboard with his wand, locking the door firmly before it has the chance to escape.

"That was fucking amazing, Jamie," he says.

Jamie looks at him, a wide grin plastered onto his face. His face bright with laughter, and Harry feels warmer than he has all day. "Come on, Dad," he says. "Language."

Harry rolls his eyes. He points his wand at his desk, and two cups of tea and a bar of chocolate appear. "Here. It'll help," he says, breaking off the chocolate and handing Jamie a generous slab.

"I thought Conjuring food was one of the exceptions of Gamp's Law of Elemental Transfiguration," Jamie says, taking a bite of it.

"I didn't Conjure it, it's in our rooms upstairs," Harry says, and hands Jamie his cup of tea. He waits for Jamie to take a sip before he speaks again. "Is that what you thought it would be?" he asks tentatively. "The Boggart, I mean. Did you think it would take that form?"

Jamie takes a sip of tea. "Yes," he says quietly. "It's just… on the train, when those Dementors arrived… I felt like I'd never be happy again. Not ever."

"That's what they do," Harry agrees. "And I agree with you. They're terrifying. Which is why it's my Boggart, too."

Jamie blinks at him, surprised. "Seriously?" If Harry isn't mistaken, he looks quite happy at that, and Harry has to force back the urge to tug Jamie into a hug right then and there.

"Seriously," he says instead. "It's been the form any Boggart takes with me, ever since I was thirteen. Lupin—Remus Lupin, Ted's dad—he was the one who taught me how to deal with them."

"Boggarts or Dementors?"

"Both," Harry says. "When I told him about my Boggart being a Dementor, he said that it meant the thing I feared most was fear, itself."

"And is that true for me?" Jamie asks.

Harry looks at Jamie, unable to hold back a small smile. "Yes, it is," he says.

"So how did you learn to get over it?" Jamie asks. "The fear. How did you get past it?"

Harry shrugs. "The same way you did, Jamie. My Boggart form hasn't changed, and I still hate Dementors. Hate the hell out of those bloody things. But you learn to deal with it. You managed a Patronus on the train, didn't you? And you managed the Boggart now."

Jamie nods proudly. "I did," he says.

Harry gets to his feet, taking the last sip of his tea. "And you'll manage it again, now."

Jamie looks a bit confused. "Again?"

"I'm technically your Defence teacher, Jamie," Harry reminds him. "Did you really think I wouldn't make you try again?"

"I think I've got the hang of Riddikulus, Dad," Jamie says.

"Not that," Harry says. "The Patronus. Practice makes it easier, you know. And I have plenty more chocolate. Do you think you can handle giving it another go?" he asks.

Jamie gets to his feet. "Yeah. I can. I'm ready," he says. "Let's do it again."

The first time Jamie faced the Boggart, it'd felt just like it did on the train. A thick fog of fear had enveloped his brain, and it'd been impossible to even think through it. It had been so convincing, is the thing. He'd suddenly felt everything he felt on the Hogwarts Express, when he'd made the decision to go investigate what was happening, when he'd had to battle Dementors next to his dad, when he'd felt as if he'd never be happy again, not ever in his life. It took everything he had to force the Boggart into tripping, and falling, and losing its power on him, but he hadn't managed a Patronus. It's why he hadn't argued with his dad about needing the practice. The last thing he needs is to be unprepared if – when – he's faced with Dementors again. He just hopes like hell that the second time will be somewhat easier.

In what seems like seconds, the Boggart emerges from the cupboard, and Jamie feels, more than sees, his father step a bit closer to his side. It's just as convincing as it was last time. Hooded, approaching them, and Jamie just knows that he won't get to it in time, he won't be able to produce a Patronus, that he'll be here forever, that the Dementor will get to him –

He squeezes his eyes shut, and focuses. He thinks of the first time he rode a broomstick with his mum, of getting his Hogwarts letter, of finding out his Patronus is the same as his dad's, and he says, "Expecto Patronum."

He opens his eyes. He hasn't managed to produce anything but silvery wisps – again with the damned mist, he thinks – but it does seem a bit more solid than last time. Or maybe it's just wistful thinking.

"Focus, Jamie," he hears his dad murmuring next to him.

The Dementor – damn it, no, the Boggart, the Boggart – moves a bit closer to him, and he shivers. It feels like every hair on the back of his neck is standing up with fear, but he looks the Boggart dead in the eye, points his wand, and says it again. He thinks of the memory of actually producing the Patronus on the train, the feeling of seeing his silvery stag stand proudly next to his father's and says it again.

"Expecto Patronum."

This time he's successful. A stag emerges from the tip of his wand, bright and warm and incredible, and the Boggart moves back.

He barely notices his father directing the Boggart back into the cupboard, too busy grinning up at his Patronus. He doesn't think he'll ever get tired of how it looks. It's the most reassuring sight in the world, he thinks. It's only once it's fully faded that he turns to look at his dad, who's beaming proudly at him and offering more chocolate. "That was great, Jamie," he says, and Jamie thinks that his Patronus is maybe the second most reassuring sight in the world, right after his dad smiling at him like that.

He accepts the chocolate, takes a bite of it. It sends warm through him, and he already feels much better. "I'm ready," he says, once he's swallowed most of it. "Let's try it again, Dad. I'll do it better this time."

After the fourth attempt, Harry decides to stop.

"What? Why, I can do more!" Jamie protests, when Harry tells him as much.

Harry smiles. The last hour, Jamie's only been growing more determined. He's gotten quick with his Patronus, quick enough that Harry is reassured that he'll be able to take care of himself if he's ever faced with a Dementor again – but Harry hopes he won't be. He's going to do everything in his power to make sure he isn't in that situation again. But he knows, from his own Hogwarts days and all these years in the Auror department, that it's better to be prepared, just in case. And he knows Jamie's prepared now. He's convinced of it.

"Not today," Harry answers Jamie. "It's not easy work, battling Dementors four times."

"It wasn't a real Dementor," Jamie argues.

"I know," Harry says gently. "But you felt like it was, didn't you?"

Jamie slowly nods. "I did," he admits. "I mean… I knew it wasn't real, but… Merlin, it felt just as awful each time. Except it got a bit better, because I got better at the Patronus, didn't I?"

"You did," Harry says, amused.

"Do you think if I become an Animagus, I'll be a stag? It'd match my Patronus," Jamie muses. "And your dad. It'd match him too, wouldn't it? And I bet it'd proper impress Leah, too."

Harry's smile fades, and he feels suddenly alarmed. "Jamie. Please don't become an Animagus," he says.

"Okay," Jamie says easily, but his smile does nothing to convince him that he plans to listen to Harry at all – but then again, Harry thinks dryly, what's new about that?

Before either of them can say anything else, the door to the classroom bangs open. Harry turns to look at the door, raising his wand immediately. He lowers it when he sees who it is.

"What are you doing here, Lily?" he asks, immediately moving closer to the door. He can hear Jamie next to him, both of them rushing because of the state Lily's in.

Lily's gone pale, and her face is covered in tear tracks. She's crying even now, and her eyes are wide, and she throws herself into Harry's arms. "Dad! You've got to come, please, you've got to come!" she wails. She sounds frantic.

Harry wraps his arms around Lily immediately. "What is it, Lils? What happened?" he asks, holding her tightly in his arms.

"It's—it's Scorpius," Lily sobs. "He's—he's—" she cuts herself off with a sob.

"What happened to Scorpius?" Jamie demands. "Where is he?"

Lily takes in a deep, shuddering breath before she speaks. "He's on—on the fourth floor. Al's with him now, and Mum—Mum said to get you, Dad. He's hurt," she says, her breath hitching in her throat at the admission. "Someone hurt him. It's bad. Really bad. You've got to come, right now."