I'm back! My thanks to Whythehellnothavefun for betaing this chapter, which puts the *content* of this fic over 50k words!

Summary of last chapter: Harry is moved to Hogwarts and begins to explore, but is shaken by his experiences with Voldemort and the Death Eaters. Meanwhile, Neville worries about Ginny, who has put herself in danger by painting treasonous graffiti in the Great Hall.

"I'm sorry, Professor McGonagall?" The door to the Transfiguration classroom creaked open, revealing a nervously-twitching second-year Slytherin. "The Headmaster wants Dean Thomas in his office."

McGonagall's face pulled tight.

"What for?" she asked tersely.

The younger student seemed to shrink. "I don't know, ma'am. I was just told by Professor Carrow to come fetch him."

Dean stood up from his desk jerkily, and his hands shook as he gathered up his pack. Professor McGonagall watched with thin lips as he left, her hand clenched around her wand. The room was quiet until the door gently thumped shut, and McGonagall cleared her throat to haltingly resume her lesson on the theory of human transfiguration.

Neville's mind could not switch back to the lesson, however. His thoughts raced. This had to be about Ginny, didn't it? Dean was a muggleborn, had shared a dorm with Harry Potter, had been a member of the DA in their fifth year, and had dated Ginny before Harry did. The Death Eaters had more reason to target him for questioning about "treason" than most. But did they suspect Ginny already? Or was it just a coincidence that Dean was the one they'd chosen to question first of the seventh years?

In the pocket of his robes, Neville palmed his DA galleon and squeezed the rim three times. His coin heated in response. It would cause the others linked to it to heat as well, and the numbers engraved on the edges to change into a row of zeroes - a signal for danger. Hopefully, Ginny would understand, and make herself scarce.

There wasn't anything else Neville could do. He forced himself to sit through the rest of the lecture, but with every moment, he was imagining what Dean might be facing right then. Walking up the steps to the headmaster's office; entering the once-cheerful room to confront Dumbledore's murderer and Voldemort himself; stepping forward and noticing the Carrows flanking the doorway behind him. Would they ask him to sit politely and spike his cup of tea with Veritaserum, or would they even bother with pleasantries before hitting him with a torture curse? Even if they got what they wanted from him - Ginny's guilt - would they continue to torture him just for the crime of his parentage?

Neville's knees bounced in arhythmic anxiety until McGonagall dismissed them almost an hour later. He practically bolted from the classroom, Seamus hot on his heels.

"Where are you going first?" Seamus asked.

"Hospital Wing," Neville responded tersely. "I doubt he's still in the office."

The two of them ran down the corridors, only slowing to a quick walk when they approached used classrooms or the noise of other people. Neville didn't want to get stopped for something as idiotic as running in the halls.

When they arrived at the Hospital Wing, though, Dean was not there.

"Was Dean Thomas here?" Neville asked Madame Pomfrey. She was giving a pepper-up potion to a third year with a runny nose.

"Should he be?" she retorted.

Neville only shook his head. "Thanks, Madame Pomfrey."

She huffed, and Neville and Seamus took their leave much more slowly than they'd come.

"Common room?" Seamus asked.

"Yeah."

They took this trip more slowly. The corridors were more crowded, and if Dean hadn't gone to the Hospital Wing, he had likely made it through the interrogation without serious injury.

Dean was not in the common room. Nor the dorm.

Colin Creevey came up to them in the common room, his face drawn with worry.

"We got the warning. Ginny ran. Don't know where."

"Out of the castle?" Neville asked, pulling the younger boy aside.

"I don't know," Colin said again. He bit his lip. "Demelza says her things are still in the dorm."

"I sent the warning when they called Dean out of class this afternoon," Neville said quietly. "We were looking for him, and we can't find him."

"You think they still have him?" Colin asked worriedly.

"I doubt they still need him for questioning," Neville said. "And his things are still in the dorm as well, so I doubt he was expelled."

That left two reasons why he'd still be missing, as far as Neville could tell: Dean was either being held to use as leverage against Ginny, or he was dead.

"We need to find him," Seamus insisted. "He could be - "

"I know," Neville said, cutting his friend off before he could frighten anyone unnecessarily. "I'll see if I can take Ernie's patrol tonight and poke around the dungeons. Meanwhile, let's pass the word on to the others and see if anyone's heard anything."

Colin nodded, looking somewhat reassured, and disappeared up into his dorm.

"Damn it, Ginny," Seamus muttered. "Why did you have to be stupid?"

Harry had thought that being stared at wouldn't bother him, not after the rumors of his being the Heir of Slytherin in second year, and after being in the Triwizard tournament in his fourth year, and then getting smeared weekly in the Prophet by the Ministry in his fifth year, and then heralded as the "Chosen One" in his sixth. There was always some reason, it seemed, for people to look up as he passed before they turned to mutter something to their friends.

Every time before, though, Harry had been able to do something about it. Look for the real Heir, prove people wrong. Proclaim his innocence, backed by Dumbledore, and prove people wrong. Start a secret student organization, find the people who believed in him, and wait until the Prophet was proven wrong. Get captured, prove his own fallibility, and prove people wrong.

Now, not only was he unable to avoid people, yell at them, fight them, or otherwise convey just how rude staring and pointing was, but he didn't have his friends with him to bolster his spirits.

He wanted Ron at his side, calling everyone who stared and whispered a tosser.

He wanted Hermione, relentlessly dragging him to the library to research and problem-solve.

He wanted Ginny, telling him to stop feeling sorry for himself because he'd show them, one day soon.

He wanted Luna, casually and kindly reminding him that most people were only afraid of the things they didn't understand.

Even Neville's shy, self-conscious reassurance that he didn't think Harry was a lunatic would have been a balm to Harry's nerves.

But Ginny had stared at Harry in horror while tears fell, and Neville had made a point to ignore Harry's presence beneath his feet.

So as Harry tried to investigate his new prison, and every few moments felt someone watching him, he'd freeze. His fins would stand on end, his heart would pound, and he'd stare back at whoever it was for an awful moment before he'd shoot away to some other part of the tank in a desperate bid for some privacy.

There were plenty of places to run to. The cylindrical tank was enormous. It must have been nearly as high as Hogwarts itself, crossing up through the already lofty Entrance Hall's roof before continuing up through the main staircase-filled thoroughfare between the different levels of the castle. The tank warped and distorted whenever a staircase swung through it, an effect which reminded Harry of the Knight Bus's nauseating ability to squeeze between other vehicles. It didn't seem to affect the integrity of the structure at all, and students on the stairs seemed used to the tank parting for them already. No water dropped through, and Harry witnessed fish being pulled and pushed out of the way along with the tank. Maybe, if he was ever insane, he could try forcing his way through the warp to land on the swinging staircase below. He rated his chances of dying by falling and by asphyxiation about equal, in that scenario.

The stand of kelp Harry had seen earlier continued up through the tank all the way to the roof of the Entrance Hall. Around and above it, the tank had several shelf-like protrusions from the walls, built of rock and coral. Many of them were homes to sea anemones, shellfish, starfish, and sea urchins. There was even a bed of muscles clustered over one of the top-most ones. Plenty of other fish were in the tank as well, at all depths. Large ones thicker than Harry's chest, tiny blue things that were smaller than Harry's pinky claw, orange-striped clown fish peering warily from inside anemones, gray fish with yellow markings the size of Harry's palm, and many more. Most of them darted away when Harry approached, though a dark fish a bit smaller than his forearm wandered up and started poking at his tail with its nose. Harry had pushed it away, not trusting anything in here not to try to take a bite out of him.

When the annoying thing tried to come back, Harry slammed it away with his tail. It finally swam off, looking completely unperturbed.

The top edge of the tank was inaccessible to Harry. He could tell it wasn't covered by glass, and that there was a stone ceiling past the water. However, there was an imposingly massive metal grate crisscrossing the tank about a dozen feet beneath the surface, preventing Harry from getting anywhere near the opening in the tank. The gaps were wide enough that Harry could reach his hand through the bars, but couldn't get his head through.

Harry tried pulling at the metal, yanking it, and rattling it. The grate didn't even seem to vibrate. In desperation, he even considered body-slamming it. But as he pulled at the bars and again felt not even the slightest budge, he had to admit he'd be more likely to break all the bones in his own body before he made any progress in displacing the gate.

There was one positive thing he'd found about the bars. Around them, the tank was surrounded by a few feet of solid stone before the walls changed to glass again. It would be difficult for anybody to see Harry up here from the staircases.

Already feeling frazzled from dodging stares and a fruitless examination of his prison, Harry floated near the gate for a while, his body bumping against the metal. He didn't know what else to do. The walls of the tank were solid glass, thick enough to distort the figures outside unless they came close. The only opening he could find was solidly blocked. Maybe… maybe if he could write a message, he could let it float up through the bars to the humans on the other side? But there was no guarantee it would be found by the right people. The opening of the tank could be right inside Snape's office for all Harry knew.

Harry berated himself for the far more obvious problem. What would he bloody write on, underwater? Even if he got some parchment, it wasn't as if he could use ink!

The hysteria was trying to overtake him again. He curled over his stomach, tail tangling into a knot, and pushed his hands against the sides of his head. His first instinct was to focus on his breathing, but even that was out of his control, now - his gills filtered water so long as either he or the water was moving. And his hands were clamped, not around ears, but around more fins.

The tension in him kept building until he screamed. The sound rippled down through the water like a sonic wave, scattering fish ahead of it as if it were a physical force.

Harry stared wide-eyed at the results, silent, and then felt his anxiety and hopelessness at being so foreign to himself keen out from his gills as quiet grief. It bounced and echoed in the water hauntingly, compounding on itself until it sounded as if multiple sirens had made the sound instead of just him.

The imaginary choir echoing Harry's sentiments settled something in his heart. He closed his eyes and allowed his quiet despondency to leave him in the form of sound again. It echoed, enlivening the water with ethereal voices that soothed his nerves.

His voice didn't sound like his own in his ears, but listening to it helped Harry feel a little less mad, and a little less lonely.

Harry stayed up by the grate for several hours. It was a respite from scrutiny, where he could put aside his fears about losing his humanity for a while and soothe his own turbulent emotions with gently hummed, wordless melodies. It banished the hysteria and the melancholy, but underneath, he could feel his uncertainty still plaguing him. He really didn't know what to do next. If he couldn't find a way to escape, what was there? Murdering fish and singing to himself like a… a crazy old maid?

Harry's brooding was broken by the muffled sound of voices coming from above him. He rolled over and peered up through the water, seeing nothing. The voices grew just a bit louder before two indistinct heads appeared far above. He couldn't make out their facial features, or their words. They looked like they were staring at him, though.

"Let me out," Harry shouted up at them, trying to infuse his words with magic. They didn't move, and he heard their voices rise in volume again.

Harry tried to wrangle his emotions and intent under his control, even while his skin itched under their examination and his ears burned with trying to decipher their speech. He tried to focus on them, and what he wanted - imagining them removing the grate.

"Let me out," he sang, and felt the magic in him take shape with the words, given purpose. He felt nothing else, though. Every time he'd imperioed someone, he'd felt his magic sink into them like a hook. His magic wasn't finding purchase in the two onlookers.

He tried one more time, with the same result. They must be shielded from his voice by charms or wards. Harry hissed at them, then dove quickly downwards. The water rushed past him, levels and staircases flying by all around him outside the glass, before he twisted his body underneath a ledge of rock just to make sure the watchers above couldn't see him.

Wasn't there anywhere in this entire place that Harry could just bloody hide?

Harry turned his eyes to look out of the tank and saw the shapes of students, stopped on a landing just below him, pointing up at him.

No, there bloody wasn't.

Harry darted still further downwards, though, feeling as if a swarm of ants was crawling underneath his skin. But there was nowhere he could stay for any length of time without someone outside noticing him.

The only place that seemed to offer true cover was the stand of kelp, but Harry remembered the slapping feeling of the leathery leaves against him and shuddered. He couldn't bring himself to withstand that again, not when he already thought he could feel ghostly touches on his arms and hips and mouth.

His fruitless quest to avoid notice, though, drove him all the way back to the ground floor of the Entrance Hall, where a narrow tunnel obscured by a fan-like protrusion of pink coral led into the rectangular tank under the Great Hall. Harry didn't pause to see if anyone in the Entrance Hall was watching before he hurtled into it, twisting his body around the crooks and bends before he shot out just above a sandy (fake) ocean floor.

He twisted to face upwards, and with relief, didn't see the soles of anyone's shoes. Long, rectangular shadows indicated the tables and benches had been replaced, but it didn't seem to be mealtime. And, as he'd noted earlier, this tank was so deep that those above would likely have a difficult time seeing him if he stayed at the bottom.

He let himself drift above the sand for a while, sliding the phantasmal touches of memory away from his arms and hips with his hands, until his heart settled into its steady rhythm again.

Finally, he relaxed enough to realize that he was starving. He couldn't figure out how long it had been since he'd eaten. Since before he'd been crucioed for snaring Snape in his magic. That had been two nights ago, Harry thought. His mind shied away from the events after that, avoiding the shadowy memories like one would a boggart. He knew Voldemort had put another fish into his tank sometime before he'd been removed from the Ministry to Hogwarts, but Harry had hardly noticed it. He had spent his time waiting to be transported again sunk in the bottom corner of the tank, arms wrapped around himself, desperately trying to retreat into sleep.

Harry examined his current options. He knew the fish swimming in a large school overhead were edible. They were the only thing he'd had to eat since being turned into a fish himself. But, Harry wasn't at all confident in his ability to actually catch one of them in this enormous tank.

He swept his eyes over the rest of the aquarium, quickly cataloging the other sea creatures trapped with him. Little colorful fish, little creatures that looked like tiny striped lobsters, actual lobsters, crabs, scary-looking eels, bigger fish with strangely pointy noses, octopuses (octopi?). Out of all of those, Harry only knew three to be edible. Fish, crab, lobster. Lobsters were fancy food, weren't they? There had to be at least a dozen of them in here, if not more. A good portion of them were sitting out in the open sand or moving slowly on top of the rocks. They looked a lot easier to catch than the fish did.

Harry swam towards the nearest one, moving carefully so as not to shoot past the creature. He'd only ever seen them dead on people's plates, on the cooking shows Petunia used to watch on the rare occasions when Vernon and Dudley weren't hogging the television. These were brown, not red, and were a lot spinier than Harry had thought they'd be. They had two long, swinging antennae at their front and prickly, pointy legs. Most of them were at least half the size of Harry's forearm. Their claws looked big enough to break his fingers.

As Harry was examining the strange creature, it turned around and caught him with a beady, stalky eye. They stayed that way for a few moments before Harry twitched, trying to edge around behind the thing again, only to reel back as the lobster shot away from him, swimming backward with the estimable speed of a bullet.

It was sheltering behind the rocks a blink later.

Alright, so maybe the lobsters weren't easier to catch.

Harry tried one more lobster to no avail, before resignedly deciding to try his luck with the fish. At the least, he knew those weren't capable of breaking any of his bones, and after the lobsters had surprised him so thoroughly, he wasn't feeling adventurous enough to try going for a crab.

The decision turned into an hour spent chasing the silvery creatures around in unpredictable circles at top speed. Harry crashed into the walls of the tank twice from not being able to fully control his momentum. Feeling bruised and humming with annoyance, Harry reconsidered his options.

By then, every animal in the aquarium was well warned of his murderous intent, and everything was keeping well clear of him. The fish were watching him with their beady eyes on the other side of the room, the lobsters had all taken cover in the crevices and holes in the rocks, and even the colorful fish Harry had already decided probably weren't edible were hiding in the seaweed and rocks. Even the scary eels had vanished somewhere.

Rather than fleeing to the rocks, the crabs had buried themselves under the sand. Harry didn't like the idea of getting his fingers pinched off by a crab any more than he did a lobster, but at least the crabs didn't look quite as menacing as their cousins, and really, they seemed like the last option for a meal.

Harry circled over the sandy floor, eyes peeled for signs of movement beneath the sand, but the crabs were hiding well.

If only he could blow away some of the sand…

Harry caught sight of the large, fan-like fin at the tip of his tail, and had an idea.

He sunk lower in the water until he was hovering horizontally only a foot over the floor. Then he kicked as hard as he could downward, again and again, and shot forward in the tank. He twisted and turned back around before he hit the rocks at the edge of the room, and saw that he had managed to cloud the water with displaced sediment. Several crabs were swimming awkwardly away, using two little fins Harry hadn't even realized they had, while others were performing quick little jumps across the floor to move quickly and begin burying down into the sand again.

Harry shot for the nearest swimming crab. It spotted him coming and waved its claws at him, but it wasn't a fast enough swimmer. Harry had it in his hands in no time, holding it from behind to avoid getting pinched. It snapped wildly, waving its legs while Harry examined it for a way to break past the shell. There didn't seem to be an easy way in.

His stomach grumbled, reminding him how very hungry he was, and Harry gave up on being methodical. He grasped one of the legs and tore it clean away.

The water clouded a little bit, and Harry tasted crab meat on his tongue. He tried to suck the meat out of the leg he'd broken and got just a taste. His teeth cracked the carapace open with a dull crack, and he set to breaking down the leg for the few mouthfuls of meat it contained.

When he was done, bits of crab shell drifting down to the bottom below, he set about eating the rest. It was a long, finicky meal. Harry cracked the carapace and spat out fragments just to get a small mouthful of meat at a time. The claws had the most, he found, and he sucked the meat from them eagerly before prying the crab's body apart with his hands.

It burst open, filling the water with its taste. Harry hesitated at the sight of yellowed guts underneath the shell instead of white meat, but a tentative bite reassured him that it was edible. Harry's starved stomach urged him to devour the remainder of the crustacean in just a few moments, leaving bits of shell and fragments of meat drifting in the water around him. Some of the larger fish reappeared and darted around him, snapping up his scraps like colorful vultures.

Harry's stomach growled again, eager for more food now that it had had something to fully wake it up again. He needed more, and was annoyed to realize he'd probably have to eat another four crabs before he felt full from them.

But, perhaps with a bit of fuel in his gut, he might manage to catch a proper fish?

Harry was more strategic about it the second time around. Instead of chasing after them like a dog after a squirrel, Harry realized he should try to corner the school against the walls. After all, the fish were predictable enough in that they always moved away from him, so if he was careful about it, he could probably back them into a corner.

It took a lot of patience. Twice, Harry lost control of the school and had to start over. He alternated between steady, patient swimming, edging closer to them while they edged away. Then they'd try to dart, and he'd have to put on a burst of speed to cut them off. It was a lot like trying to herd a flock of snitches.

Harry pushed away his frustration and kept at it, until finally, he managed to chase the school into a corner of the tank, up by the glass ceiling.

His heart beat in exhilaration at the success, and his entire body was tense, preparing for the final play where he'd either come away with a worthy dinner or fail yet again.

Think of the snitch, think of the snitch, Harry told himself. Then he burst forward, straight into the midst of the school. Silver flashed around him and fins scraped against his scales. The fish moved so quickly that it was hard to pick one out among them all. Harry managed to lock onto one of the straggling ones, though, and on instinct, his hands flashed out towards it. He felt slippery scales under his fingers and drove his claws into flesh. The water around him cleared, leaving the one fish he'd caught struggling uselessly in his hands.

"Gotcha!" Harry crowed, twisting back down towards the bottom of the tank with his catch.

It tasted like the best fish he'd ever eaten.

When Neville and Seamus trudged into the Great Hall for dinner, they hadn't managed to learn anything else about Dean. Word had gone out to the entire DA, but no one had seen him since Transfiguration. Neville's feet felt weighted by the sense that something horrible had happened to his friend and the hopeless fear that he couldn't do anything about it. Nobody had reported seeing Ginny, though, and Parvati had heard rumors that the Carrows were in a fury. As Neville sat down, he glanced at the head table. Snape, Voldemort, and the Carrows were all missing.

Neville hoped that that meant Ginny had gotten away safely.

"What's going on there?" Seamus asked, frowning around the room. Neville turned from the head table and realized that there were dozens of students looking down into the tank underneath them, pointing and chattering. Neville stood back up and looked down between the tables, and his breath caught at the sight of the siren several dozen feet below, zooming back and forth through the water, apparently herding a school of fish into a corner of the tank.

"You think he realizes we're up here?" Seamus asked, coming to Neville's side.

"I doubt it," Neville said. Harry seemed intent, not once glancing away from the silver-scaled creatures he was corralling. He swam with astonishing speed and was able to make hairpin turns without losing momentum.

Neville and Seamus joined other students in gathering closer to the corner of the room nearest the Slytherin table, where Harry was driving the fish. In a few minutes, the fish were crowded so high in the tank that their bodies slipped along right underneath the glass, flickering madly with panicked movement.

Someone screamed, and many students jumped away from the corner. The silver fish shot away as well, scattering like rays of light, allowing Neville to catch a glimpse of dark scales brushing underneath the glass.

"Did you see that?!" someone was shouting.

An excited chatter rose up from the students as they began to break up. Neville stared down, squinting, and caught a glimpse of Harry swimming at the bottom of the tank, a bleeding silver fish caught in his hands. Harry bit down into the fish's side while it was still squirming, and Neville turned away, stomach queasy.

He knew Harry needed to eat somehow, and it wasn't as if anyone was going to serve the newly-minted siren a shepherd's pie on a silver platter underwater.

Yet, that knowledge didn't make what Neville had just seen any less jarring. The Harry Neville knew would never willingly hurt a living thing outside of self-defense. But the siren version of him seemed to have no hesitation in eating a fish while it was still alive. It didn't match. It wasn't right.

When Neville had realized that Harry still carried his human emotions - hatred for Snape, affection for Ginny - he'd assumed that that meant that Harry's mind was unchanged. But was it possible that it had been, as Voldemort and The Daily Prophet were saying? But, unlike what the propaganda was pushing, could Harry have been fundamentally changed and still remain him?

Neville rubbed his forehead as he sat back at the table, ignoring the talk around him. Trying to figure out the details of the impact of the ritual performed on Harry was a futile task, he quickly realized. Especially until he had more evidence to use. Perhaps they'd learn more soon, after they found a way to make contact with their forcibly estranged classmate.

Neville forced himself to eat a small plate of roast chicken and vegetables and tried to put his thoughts back into order. His priority needed to be "bumping into" Ernie MacMillan and swapping patrol shifts with him.

Ernie was scheduled to patrol the dungeons tonight with Parkinson, who Neville was reasonably certain he could shake with minimal effort. Her disgust for anyone not openly allied with Voldemort was well known, and she often found an excuse to go off on her own, if she bothered to show up for patrols at all. Apparently, she considered doing rounds to be beneath her, now that she was Head Girl.

Combined with Malfoy's lack of attention to his Head duties, Neville would likely be able to poke around in the dungeon, free of suspicion, for several hours. There would be no written record of the swap, and if anybody ever questioned Neville or Ernie about the change, there were any number of excuses that could be made.

Hopefully, Neville would find some clues as to what had happened to Dean.

After his dinner, Harry decided to poke around the corners of the Great Tank (as he'd somewhat sarcastically dubbed it) for anything he could exploit. The ceiling still showed that students hadn't yet arrived for their own meal, so Harry felt free to poke his sharp-tipped fingers into the crevices and corners at the top. The glass seemed to be fused directly to the stone walls and was at least a foot thick. Even pressed against it, Harry could still see that the join of glass and stone on the air side was significantly higher up.

The walls of the tank were no weaker. They appeared to be carved out of a single piece of gray rock, and there was no seam or crack in any part.

Closer to the floor, the rocks and corals provided a much less solid barrier. They were riddled with narrow holes and crevices, most of them too small for Harry to pass through. Fish darted in and out of the gaps, and lobster antennae waved out from underneath ledges of rock hanging over the sand. Harry didn't find any gaps big enough to fit more than his arm, and they all seemed to twist and turn too much to even determine if they led out of the tank itself or if they were just a network of small tunnels contained within the tank.

Above, the shadows of shoe soles indicated that the Great Hall was beginning to fill for mealtime. Harry frowned, tucking himself into a scant shadow next to the rocks, and watched as far above the students rushed to one of the corners of the room nearest the entrance and Harry's tunnel underneath. He saw a few pointing, but there was nothing there.

Still, the attention on the tank made his fins stand on end, so he darted across the floor as unobtrusively as he could manage and slipped into the shadowy tunnel that led to the columnal aquarium in the Entrance Hall.

Poking his head above the tunnel, Harry frowned at seeing students leaving the Great Hall.

Hadn't dinner just been starting?

He stayed, mostly hidden by the tunnel and peering out from underneath the coral, watching. The students were definitely leaving in the usual groups, looking exhausted and downtrodden to the last. There was no sign of people arriving to eat, as Harry had just seen from inside the tank under the Great Hall.

He pushed himself backward through the tunnel (it was too narrow to turn himself around in) and awkwardly emerged back into the Great Tank. Sure enough, it seemed from in here that there were still students arriving to eat, with a good few already settled at tables. Harry watched carefully to make sure he didn't see anyone coming in, then swum back up the tunnel and peered out.

Yes, this side still showed people leaving.

His stomach felt cold. Both couldn't be true. One tank or the other had been spelled to show him something false, and he was clueless as to what was real. He'd seen people react to him from both tanks - when he'd first been pushed in, and everyone had scrambled away from him and Ginny had been crying; and when he'd seen Susan and Hannah watching him in the Entrance Hall, along with several others who had stared and pointed.

Harry stayed hidden in the tunnel, and no one outside noticed the top of his head poking out from between the corals. When it seemed that the flow of traffic had died, Harry kicked out into the tank, reassured himself of the emptiness of the Great Hall's threshold, and then turned right back around into the Great Tank.

It still showed people sitting above, eating.

Cautiously, Harry swam upwards towards the Gryffindor table. For the most part, he couldn't really get a look at people's faces, as they were obscured by the combined shapes of benches, legs, and tables. Swallowing down his anxiety, Harry rapped on the glass underneath a pair of feet that maybe belonged to Colin Creevey. There was no reaction from the other side, and Harry rapped again, harder. He could hear the echo of it in the water, but there was still no sign that anyone had heard on the other side.

Harry swam around until he was between the Gryffindor table and the edge of the Great Hall, behind people's backs. No one took notice.

"Hello?" Harry asked, emboldened.

Nothing.

"Hello!" he sang, far louder.

Still nothing.

It was possible that they couldn't hear him, wasn't it? Voldemort wouldn't have given Harry the ability to imperio the student body.

Harry swam carefully just underneath the glass, passing beneath the Gryffindor table and into the aisle between it and the Hufflepuff table. Still, no one seemed to notice, so he began making circuits of the room, swimming up and down the aisles, peering up at the forms on the other side of the glass, looking for any hint that they could see him. They loomed far larger than was natural above him, even though they were seated, and it was disconcerting to be so close to them without drawing the slightest notice.

If it was even real.

Harry wasn't sure either way until a Hufflepuff student got up from the bench and walked straight over Harry without even blinking, her eyes downcast but brushing right over him. A Ravenclaw boy followed, behaving exactly the same.

What Harry saw there wasn't true.

The conclusion spawned more questions. Was what Harry was seeing now entirely fabricated? Had it happened, but in the past? What purpose was there in showing Harry something faked? Were the students seeing Harry as he was, or were they being shown a fake image as well? Was this effect localized just to this tank, or was what Harry had seen out in the Entrance Hall also a lie, just a different one? If so, why? And had the spells only come into effect very recently, since Harry had seen people react to his presence earlier, or was that another layer to the deception?

When Harry went back to the tank in the Entrance Hall, the room was empty of students. The vaulted windows above the great entrance doors showed that it was dark outside. Torches still burned around the edges of the Hall, though, so he was reassured that it was still before curfew as it should be.

Despite that, the hallways were practically deserted. Harry swam slowly up and down the tank, peering out into the torch-lit shadows, and batting away that irritating fish from earlier that seemed determined to come to sniff him for some reason. The shadows engulfed the tank, which didn't have a light of its own, and soon enough, even the torches out in the halls winked out.

The quiet quickly became too much to bear as Harry drifted in the darkness. His chest thrummed with nervous sound, wavering up and down in low notes, while his eyes darted from shadow to shadow in the water. He could still tell the difference between the fish and could pick them apart from the kelp behind them and from the rocks. But everything was still darker, less colorful, and less friendly. It was all too easy to imagine a shark rising from below him with its jaws wide open.

He shuddered. He was exhausted, he realized, and should probably find somewhere to sleep. Fake-sleep. Whatever it was.

He already knew his body tended to bump around while he slept, though, so he couldn't imagine just letting himself sleep anywhere. And, while he seemed able to control his depth in the water in the same way he moved his muscles, he couldn't make himself heavy enough to truly lay down.

He hesitantly swam from rock shelf to coral reef, up the length of the tank, looking for somewhere he might be able to wedge himself for the night. Nowhere quite seemed to suit. Harry had just decided his best bet would be to twist himself into the tunnel if he didn't want to drift around while sleeping, and had turned to swim back down when he heard something out of place.

An echoing vibration, dulled, but rhythmic. The sound of something hard striking something hard. A knock? Harry couldn't imagine anything in the tank making that sound.

His heart leaped into his throat. He spiraled down the tube of water, dodging the larger fish that resembled floating rocks and forcing aside the smaller ones. It only took him a moment to descend into the Entrance Hall. Someone was standing at the base of his prison, rapping a fist against the glass and looking over her shoulder. Her hair flickered red in the moonlight.

Ginny.

Harry dove down to the floor's level, then twisted himself upright to look at her face-to-face. He pushed himself against the glass, bracing himself with his hands flat against the curved surface; sorrow and happiness mingling in a high-pitched, dipping note that sailed out from his heart. Ginny pressed her hands opposite from his, a foot of glass separating them. Tears dripped down her cheeks.

"Don't cry," he murmured gently, knowing she couldn't hear.

He saw her lips move, and part of it may have been his name, but Harry was just as cut off from her speech as she was from his. Her eyes locked onto his, desperate and searching, for what, Harry didn't know. He pushed closer until his forehead was against the glass, thoughtlessly crooning a wordless feeling of comfort and affection towards her.

He saw her shoulders loosen, and she appeared to sniff back her tears and chuckle. Harry smiled at that, wondering what on earth she found funny, and she smiled back at him.

She wasn't scared of him.

Of course she wasn't; this was Ginny. She'd fought Death Eaters with him when she was only fourteen.

She said something else, then reached into a pocket in her robes. She pulled out a sheet of parchment, which she then unrolled and carefully pressed against the glass. Harry shifted to read it, his heart beginning to race as he realized it was a note written in her hand.

Whatever happened, it wasn't your fault. I know that's what you're thinking. But it isn't. So stop it, got that?

Harry laughed disbelievingly, feeling lighter at her immediate, predictable effort to counter his usual thoughts. He didn't believe it, but the reassurance was so like her. It proved she still knew him. It proved Harry still had people who cared.

I also know you're still you, no matter what that foul reptile did to you. Some of the others think you've lost your mind from a bit of magic, but I and others can tell that's not true. We'll keep up the fight however we can. We won't rest while skull-head reigns. He wants you to serve as a reminder not to oppose him, but we won't let your sacrifice be for nothing.

Harry hummed nervously at the bold words. They reminded him uncomfortably of dramatic scenes in movies where a band of rebels got together for one last suicidal attack.

Keep yourself alive. If we ever get the chance, we'll get you out of there. Neville's trying to work out a way to talk properly, at least. I did something a little stupid so I probably won't be able to come back, but I've got it all figured out, so don't worry about me. I've missed you every-

The parchment dropped away before Harry could finish reading it, landing on the ground. Ginny had turned and sprinted away down a darkened corridor. Neon spellfire followed her, splashing into a wall where she'd been a blink earlier.

Harry spun in the water to see a professor he didn't recognize running from the other side of the Hall, hurtling full-tilt after Ginny. It was a woman with a shovel-like face and a mean expression, her hair pulled back into a bun that would have made even McGonagall wince. She raced straight past Harry without a second glance, shouting something lost to the barrier between them.

Harry stared into the corridor they'd disappeared down, fear and horror and helplessness all mixing until he yelled out into the water and slammed his fist against the glass. The fish around him scattered.

He waited for minutes on end, but there was no further sign of Ginny and the professor.

What kind of trouble was she in? What had she done? What would they do to her if they caught her?

He lingered there, hoping irrationally that Ginny would come back, the shovel-faced woman lost. He hadn't even gotten a chance to finish reading her letter. It was laying on the floor within arm's reach of the tank, if only the glass didn't present such an insurmountable barrier. It had curled up without the pressure of Ginny's hand to flatten it, concealing the rest of the message within.

Another yell of frustration ripped from him, echoing around the tank like the discordant clanging of bells.

Still, he didn't leave.

He waited, and waited.

Finally, there was movement on the stairs. Harry pivoted to face it and saw Snape, flanked by the shovel-faced woman and a tall man who, instead of resembling a shovel, appeared to have been smashed by one. Snape swept down towards the letter left laying on the ground, the other two at his elbows like the billowing sleeves of his cloak. Harry's fins stood on end and he hissed, baring his teeth, at the lot of them. Snape glanced at Harry, sneered, and scooped the letter up. The parchment disappeared into his robes as if he'd vanished it.

The three stood where Ginny had not so long ago and had some sort of discussion. Harry circled tightly just by them, straining to hear even the slightest hint of their voices, their tones, anything. Snape and the other man's faces gave nothing away, and the woman had put her back to Harry so he couldn't see her expression.

Whenever Snape's eyes flickered over to Harry, Harry made it a point to hiss.

Merlin help the miserable traitor if there was ever a time when Harry wasn't separated from him by dragon-proof glass.

Finally, the group broke up. Snape swept away like a greasy shadow, while the other two turned to go a separate way together.

The woman's face looked victorious.

Back in the seventh-year Gryffindor boys' dorm, Neville had just started to fall asleep after a fruitless patrol when the sound of the door opening startled him awake. He was out of bed a moment later after he recognized Dean.

"Are you alright?" Neville blurted.

Dean looked up at him, eyes red-rimmed. "They caught Ginny."