“I don’t understand,” said Harry. 

The two professors and Harry were in the quarantine room of the hospital wing, which was sparsely furnished with three beds and a small area with a low table and a few armchairs, presumably for the use of patients that had mostly recovered but were still infectious. While Harry dumped his satchel next to a bed, Dumbledore lengthened the legs of the table so that they could stand around it, since somehow the situation didn’t seem to call for sitting in a squishy armchair. 

The three of them looked again at the map, which Snape had spread out on the table. Inside the Defense Against the Dark Arts Office, a dot labelled Alastor Moody remained, unmoving. And, pacing back and forth, was another dot— a Bartemius Crouch.  

“Hmm,” Dumbledore said. He tapped his chin thoughtfully. “How very interesting.”

Interesting? Obviously, their theory had been all wrong. Moody was right there in his office. Harry, with a sinking feeling, wondered if all that awfulness with Snape in the corridors and the common room, had been for nothing…

But— 

“Why would Crouch be in there?” Harry asked. “I thought he was really sick.”

“Young Mister Weasley has been covering for him since the Yule Ball,” Dumbledore said thoughtfully. “I have not seen Mr Crouch since before then. He has no reason to be in the castle if he is indeed very ill— and in any case he has no reason to consult with Alastor Moody. ”

They looked at the map for another long moment as the dot labelled Bartemius Crouch finally stilled, as if its owner had just sat down.

“Long-term polyjuice potion use does need a constant supply of donor material,” Snape said slowly. “And he has no alibi. Unlikely as it seems, Bartemius Crouch could have been impersonating Moody since— when did he purport to fall ill? December?”

“But,” Harry said confusedly. “Isn’t he the head of the Department of International… something? He’s not a death eater. Why would he do that?”

“The Department of International Magical Cooperation,” Dumbledore corrected. “And he used to be the head of the Department of Magical Law Enforcement, where he demonstrated a most profound loathing of Death Eaters and dark wizards.”

Snape’s face twisted into a scowl. “That man also demonstrated a loathing for justice and humane treatment of prisoners.”

“That does not remove the fact that almost anyone else would be more likely to take part in a Death Eater plot than Bartemius,” Dumbledore said.

“Maybe it is someone else stealing the things for polyjuice,” Harry said doubtfully. It had made so much sense… but perhaps Moody really was just the kind of person who used the imperius curse on students to help them gain a resistance against it. “Or— are they friends?”

“Friends?” Snape said incredulously. 

“They would have worked together,” Harry said. “They could just be visiting.”

The potions master scoffed at this, which Harry gathered was to indicate his doubt at either Moody or Crouch having friends. 

They all kept looking intently at the map for a few minutes more, but it seemed that neither Crouch nor Moody were going to be moving anytime soon. 

“There is a better way than this speculation,” Snape said eventually. “One of us finds the apparent Moody, takes him somewhere else, while the map is being watched. If there is polyjuice involved it will become apparent. Or we could simply enter his office and see if Bartemius is indeed present.”

That seemed to make sense.

“A sensible plan,” Dumbledore agreed. “And I’m sure Alastor, if it really is he, would forgive us some slight paranoia in these apparent circumstances,” he added, a twinkle in his blue eyes. 

Constant Vigilance! thought Harry.

Snape didn’t say anything but it was clear he thought Moody would grudge Snape for it.

Soon it was settled that Dumbledore would go to the DADA office, armed with the marauder’s map so that he could check that the same dots were still there just before he entered. If there was no Crouch in sight but the map said that he was present, then he would ask the supposed Moody to accompany him to his own office, where they could “discuss the events of the second task”. Snape would be waiting there and they would subdue the imposter and wait until the polyjuice had worn off. 

And Harry would remain all the while in the quarantine room of the hospital wing. After all, the Headmaster reminded Harry, the possible-imposter already knew about his supposed suspension. It would tip him off if he saw Harry. 

Not to mention that neither the Headmaster nor Snape would have countenanced any notion of involving Harry anyway. They had made that quite clear in Dumbledore’s office earlier.

Ten minutes later the Professors were ready to act. Dumbledore sent Snape on his way to the Headmaster’s office first, so that he could have time to alert Professor McGonagall on the way, then raised his wand. 

Harry watched the gold-lace wards crackle into being, rather awed. They were embedded in the stone walls of the room, and danced round the window-glass in flecks and shimmers. Even the floor and ceiling had traces of it. 

“No-one shall be able to enter, now, except for me.” Dumbledore said. “Nor will you be able to exit. The quarantine wards are specifically designed so that the only allowed entrance or exit is that of the caster, and only the Hogwarts Mediwitch and the Headmaster are able to raise them.”

Harry nodded his understanding as the golden ward-magic slowly settled into the walls, fading until no longer clearly visible.

“I shall be on my way, now,” the Headmaster said. “I shall return anon.” 

And then he was gone.

Waiting was difficult.

Part of Harry was fine with it— happy to not have to do anything about a danger in Hogwarts, for once. A resentful part of him prodded at that feeling and murmured that the teachers should probably have noticed an imposter in their midst well before now… 

But although Harry felt he should feel reassured that it would all be taken care of, deep down he was not reassured at all. 

He sat on a neatly-made bed and stared blankly out the window, legs jittering; then stood up abruptly and paced over to one of the armchairs before flinging himself on it dramatically.

After all, though Dumbledore was powerful and Snape was nastily clever, in the past it always had come down to Harry in the end— and Harry was lucky and quick and doing well in the tournament alongside the best and brightest students of Hogwarts, Beauxbatons and Durmstrang. Harry had killed the basilisk and defeated a horde of dementors with his patronus…

If Snape was here, Harry thought as he drummed his fingers on his legs, then he would be calling Harry a conceited little brat— and he might be right, a little. But if Harry was conceited then it was because he had earned his conceitedness from acting while teachers did nothing. If it wasn’t for him, Ginny would still be down in the Chamber of Secrets, decomposing and rotting…

Stop it! he thought fiercely. Stop it!

 Unsettled at the turn his thoughts had taken— was he really that selfish and disgusting?— Harry pinched the soft underside of his arm cruelly. When the pain from that had faded away he vowed not to think about that any more. Instead, he tried to see where the web of golden magic had faded into the walls, and blurred his vision in and out trying to trace the delicate lines of it.

In the end, Harry had fallen asleep on the armchair, exhausted after his late night and the emotional rollercoaster of the second task. The chiming sound of the wards disengaging stirred him, and he woke up just as Professor Dumbledore stepped into the room, followed by Snape.

“Did you catch him?” Harry asked eagerly, suddenly very awake. Almost immediately he flushed at the question.

“Yes,” Dumbledore said. 

Harry shifted into a better position to listen, wincing at the ache in his neck from sleeping upright. 

“And?” he asked. He heard a slight scoff from Snape then, presumably at his lack of manners.

“He is secured in the dungeons under the supervision of Professor Flitwick,” the headmaster said. “And  he will be going back to Azkaban once the DMLE have finished arrangements,” he concluded.

“Back to Azkaban?” Harry said curiously. 

Dumbledore nodded, his beard bobbing up and down. “It seems that the real Alastor Moody has been living at the bottom of his own trunk for months, whilst one Bartemius Crouch Junior (formerly imprisoned for torture of an innocent family but rescued from Azkaban by the questionable actions of his father) has been impersonating him in a convoluted plot to resurrect Lord Voldemort. The man engineered your entry into the Triwizard Tournament and has been trying to ensure that you are the winner so that when you touch the cup in the final task you are whisked away to the Dark Lord by a hijacked portkey so he can use you in a horrific resurrection ritual.”

“Oookay,” Harry said. That did seem very convoluted. “That sounds like the plot of a weird novel.”

Dumbledore nodded, eyes twinkling. “I’m sure it would have felt less weird and more horrifying if it had succeeded.”

Harry thought that this was quite probably true. 

“Well, I should get back to work,” Professor Dumbledore said. “Though, there is one more thing, Harry—”

The boy looked up at him curiously. 

“If I’m not mistaken, your godfather’s case will soon be reexamined. Because the imposter claimed to be colluding with one Peter Pettigrew, assumed to be deceased, doubts have been raised about that whole matter, especially since there was never a trial in the first place… so, there is reason to believe Sirius Black may be exonerated in due course.”

“Really?” Harry said, bubbling with excitement. “Really? Oh, professor, that’s wonderful! I—”

He broke off, suddenly awash in unfulfilled daydreams. Sirius would be free, and he’d stop eating rats and live in a house with Harry, they’d eat three full meals a day and Sirius would let Harry eat pizza, he was sure, and they’d buy new clothes together… Sirius would ruffle his hair and hug him tightly… he might even tuck Harry in at night, and even if Harry was probably too old for that he didn’t really care… he’d buy him birthday presents and they’d play pick-up quidditch together and go bowling and swimming in the ocean, Sirius would teach him—

“Don’t get too excited, Potter,” Snape growled. “Nothing’s happened yet and your mutt is still a flea-infested fugitive. Personally, I wouldn’t be surprised if nothing came of it. It’s not as if the ministry is known for integrity and fairness, though of course if it were they ought to lock Black up again…”

Harry was happy enough that he wasn’t bothered in the least by Snape’s pronouncement. “A bit of excitement isn’t a bad thing,” he said exuberantly. “I’d rather be optimistic than never happy at all li—”

He caught Snape’s eye and decided that the sentence was better unfinished. Flushing, he turned away to look at the headmaster. “Thank you,” he said fervently. And then, deciding that he really ought to, he looked back at Snape. “And thank you, professor.”

Professor Snape blinked at Harry, looking at him as if he were an utterly perplexing species of potions ingredient. Ha! Harry thought. It was rather fun confusing Snape in this way. 

“Thank you, Harry,” Dumbledore said gently. “I’m proud of what you’ve done today.”

Harry squirmed a bit. He hadn’t actually done anything— had he? Just talked about what he thought, and sat there for hours while the teachers had done everything, trying to trust that it would work out all right—

The headmaster inclined his head. “Precisely,” he said. “Well done.” And then he left— but not before extracting the marauder’s map from his pocket and giving it back to Harry, who put it in his pocket before Snape might get it into his head to confiscate it or something.

Snape and Harry were left together in the isolation room, but it only took about a quarter of a second before Snape whirled round and followed in Dumbledore’s footsteps. Harry, still caught up in thinking about what Dumbledore had meant, noticed his potions professor was leaving only when the door closed behind the man.

“Wait—” he muttered to himself. 

He leapt up and scrambled out of the room, into the main ward of the hospital wing. Somehow, breath heaving, he managed to get in front of Snape in such a way that the man stopped abruptly, cut off in his path.

“Professor,” Harry said, boldly. “Now that the imposter’s been captured, you can take this off me.”

He gestured at the collar round his neck, and the wretched bell dangling there.

Snape twisted his head to stare at Harry, in a long moment of silence. Harry stood his ground, and made sure not to say anything further, because he knew he’d probably tie himself in knots with Snape looking at him in that way.

Eventually Snape lifted his wand, and prodded it at the collar round Harry’s throat. The boy barely kept himself from making an undignified yelp at the contact, his hand flying up to his neck. But then the collar was falling away, split in half.

Holding the leather strap in his hands, Harry wanted to grin and grin and grin. He hadn’t actually expected Snape to take it off, somehow…

“Thank you,” he burst out. “Thank you, thank you—”

Snape took the collar from Harry and placed it in the pocket of his robes.

“Detention,” he said crisply.

Harry’s jubilant mood burst like a soap-bubble.

“What?” he said. “But—”

“You didn’t think I’d forgotten, did you Potter?” Snape said smoothly. “Out after curfew, snooping through the restricted section of the library, collecting yourself inappropriate reading matter… but as I am feeling— lenient—” his lip curled as he spoke the word, “you are only receiving detention.”

Harry opened his mouth, but found he had nothing to say. Snape was right— for him, this was being lenient. 

“Actually,” Snape was saying, tapping a finger on his chin in a parody of contemplation, “Perhaps you are right, Potter. I am being too soft. Better make it two detentions, and thirty points from Gryffindor.”

Badly wanting to roll his eyes, Harry said, evenly, “Fine.”

“Fine, sir.”

“Of course, sir,” Harry said. He stepped aside and watched as Snape let himself out of the room, black robes furling with a dramatic flick. Rolling his eyes, he opened the door again and left himself.

Harry was halfway to Gryffindor tower when he had the sudden, horrific thought that all of that—theatricality—was Snape being playful.

Urgh.

But Harry pushed it out of his mind as he skidded round the corner, nearly tripping on the flagstones in his haste to speak with Hermione and Ron. Snape and his detentions could wait; Harry needed to tell his friends what had happened.

Everyone had sat down to dinner that night as usual, even if a good part of the school had been peering curiously at Harry. But before the food could appear, Dumbledore tapped his wine glass with a delicate ting and stood up. 

“Dear students,” he began. “Before we begin our suppers, there is an announcement that needs to be made.” 

When everyone had shifted to look at him, the headmaster continued. “It is my regret to inform you that our Defence Against the Dark Arts professor has been arrested.”

There was silence for a moment, then the hall broke out into talking. Dumbledore allowed this for about thirty seconds, then clapped his hands for silence. 

“And this professor,” he said, “was not Alastor Moody, but instead someone using polyjuice potion to impersonate him as part of a nefarious plot. In fact, he was a marked death eater who confessed under veritaserum to a plan to resurrect Lord Voldemort.”

Many of the students flinched at hearing the name, as did a few of the professors.

“And so, alas, I will once again be searching for another DADA teacher,” Dumbledore said. “On a happier note, a round of applause for Harry Potter and Professor Snape! It was they who discovered that our Defence teacher was using polyjuice potion, and it was their acting skills that meant that our imposter was able to be safely captured.”

And he led a round of confused applause from the staff and students, who all looked rather bewildered by this turn of events but nonetheless followed the headmaster’s lead. At the professor’s table, Snape didn’t appear to be too happy to be associated with Harry in such a way, but as this wasn’t too different to his usual dour expression no-one took much notice.

Dinner that night was much appreciated by Harry, who was now realising that he hadn’t eaten since last night— well, unless you counted the gillyweed, which Harry did not. Everything tasted especially good in his hunger. Wedged between Hermione and Ron, he felt quite content. Enough so that when Cormac McLaggen asked him, rather aggressively, “So was all that pretending, then?”, all he did was say an unconcerned yes and ignore him. 

On the whole, thankfully, the news that their teacher had not actually been Moody turned out to be rather more interesting than Snape threatening awful punishments to Harry, even if the man had turned out to be pretending.

After a second helping of treacle tart, Harry, Ron and Hermione went up to the common room to talk further about everything that had happened, which somehow turned into a debate about what the actual Alastor Moody might have been like as a teacher… then Harry was watching Ron build a card house with exploding snap cards… and then he must have fallen asleep in his armchair, because Hermione was gently shaking him awake.

He staggered up to bed and after a half-hearted toothbrushing slumped on his bed and fell asleep again, barely managing the energy to pull his covers over him. 

It had been too long since he’d slept properly. Tonight, there was no bell to disturb his dorm-mates, no anxiety about the second task, no wondering where Ron and Hermione were... 

Tonight, there was only sleep: soft, dark, and overwhelming.

The End.