A/N: Thanks to everyone who's sticking with this story despite my ridiculously slow update rate! I should have known better than to try to juggle as many writing projects as I currently am, but... oh well. And, this chapter was a real struggle. I wrote three separate versions of it before finally deciding to go with this one, even though I'm not entirely happy with it.

Oh, and thank you to everyone who left a review! I really love responding to reviews when I can, but I can't reply to your questions if you're commenting as a guest, so just, keep that in mind.

I had a reader or two request artwork to help envision Harry's siren form. There is some of my art posted on the Ao3 version of this fic, as well as a link to one of my Pinterest boards full of merpeople depictions that inspired me.

Finally, Thanks to Whythehellnothavefun and AngstySnake for beta reading this chapter!

Last chapter summary: Dean is summoned to the Headmaster's office, and Neville tries to warn Ginny of the danger using the DA coins. Meanwhile, Harry figures out hunting, before discovering that there is magic on the tank distorting his view of the outside. That night, Ginny pays Harry a visit. Harry doesn't have time to finish reading her letter before Alecto Carrow appears and chases Ginny into the corridors. Dean shows back up in the Gryffindor boys' dorms in the wee hours of the morning to reveal that Ginny was caught.

After Dean's startling entrance and announcement, Neville stood in shock. Ginny had been safe. No one had known where she was.

At least, Neville had thought so. What had happened that she had been caught?

"How do you know?" Neville asked.

"They only let me go because of it," Dean said, sniffing. One of his eyes was puffy and bruised, and his robes were sweat-stained and disheveled. Seamus tugged their roommate into the room and shut the door behind them. Dean jumped at the sound of the latch, then hesitantly sat down on the edge of his bed, facing them.

"They were trying to use me to draw her out," he said. "Didn't need me anymore once they got her and told me so."

"Did they say how they found her?" Neville asked.

Dean shrugged, then winced. "Carrows said something about Harry, but I'm not sure what happened. They had me in this little cell somewhere in the dungeons. It's a maze down there and I'm not sure I could find my way back even if my head was clear."

Neville ran his fingers through his hair. Of course. Ginny hadn't wanted to leave before trying to reconnect with Harry - a doomed romance if there ever was one, but everyone had known her feelings were still strong. Snape might have known about the two and set someone to watch near the Entrance Hall for her. Dean had probably just been backup in case she didn't act on her first, impossible impulse.

"Let me help you get cleaned up," Seamus said to Dean, looking worried.

"I just want to sleep," Dean said in reply, but stayed sitting up on the edge of his mattress. He turned to Neville. "We're going to get her, aren't we?"

How? Surely it would be impossible, and the idea of something so risky was already making Neville feel a little bit queasy.

Yet, that was the question he was asking himself: how. Not if.

"Yeah," Neville said heavily. "Somehow."

Both the other boys looked far too reassured; and Neville wondered when shy, chubby, untalented him had become the one they all looked to.

Dean went to clean himself up after all, despite his earlier claim and the late hour. Meanwhile, Neville and Seamus quietly discussed possibilities and options. The chances were high that Ginny was already outside of Hogwarts, and if that was true, there was little chance that anyone inside Hogwarts could help her.

But, if she was still being held in the castle, she would probably be kept in the dungeons like Dean was. Probably. But Neville had been down there for hours patrolling and hadn't seen the slightest hint of any cells, so who knew if they'd be able to find her?

They also didn't know if she was there already, or if she was somewhere else being interrogated. They didn't know how much time they had. They didn't know what the Death Eaters' plans for Ginny were. They didn't know if Voldemort had left or if he was staying in the castle.

They didn't know anything, really, and the two boys quickly realized that forming any sort of break-out plan was useless until they had more information.

"So what's the plan?" Dean asked, coming out of the bathroom looking weary, but at least clean. He'd put on his muggle football pajamas.

"Call a meeting," Neville said.

"That's not going to do anything," Dean started.

"We can't do anything without knowing something," Neville said. "And we can't just run into the dungeons hoping to find Ginny and accidentally run straight into You-Know-Who."

"She might not have that kind of time," Dean pressed.

"We know," Neville said. "But if we act now we're more likely to all end up dead than we are to do Ginny any good."

"Hopefully they'll want to make an example out of her," Seamus said. "What she did to get in trouble was public, and if they don't address it publically, that's a problem for them. They might make some sort of announcement, or release something to the Prophet, tomorrow."

"Or she might be dead," Dean said.

"She might already be," Seamus said, even quieter.

Neville took a deep breath. "That isn't going to get us anywhere; we can't do anything tonight. Maybe we'll learn something at breakfast. Else, we'll meet up with anyone who's free after Care and try to make some sort of plan then."

Reluctantly, Dean nodded.

None of them slept well that night.

After seeing Ginny chased, Harry stayed up the rest of the night, combing up and down the Entrance Hall for any sign of movement outside. He had a bad feeling that whatever it was that Ginny had done was pretty bad, and an even worse feeling that she hadn't managed to escape the shovel-faced woman. What would they do to her? Would she be okay?

Aside from the smashed-face man patrolling, and the appearance of a few ghosts drifting past outside, there was no movement all night.

Finally, light broke through the windows high in the Entrance Hall. Harry realized he'd been drifting listlessly at the bottom of the columnal tank for some time, staring out towards the main stairway down to the dungeons.

With a glance back out into the brightening halls and a heavy heart, Harry finally admitted that anything important that had happened during the night had likely taken place well out of his sight. There were at least two secret passages that bypassed the main staircase into the dungeons, and the Slytherins probably knew of more. The castle was a tangle of corridors and secrets, and even if Harry was positioned in the main hub, many of the castle's more experienced residents would use alternative routes.

Harry started to move, not entirely sure what his plan was, and realized there was a slight bit of drag against his tail. He looked down and realized that the weird fish that had been trying to sniff him ever since he'd gotten here had found him while he'd been staring out, and had somehow attached itself to his tail. Harry yelped, somersaulting halfway across the tank, and frantically swatted the thing away. There was no blood and no bite marks, but it still looked like an overgrown leech with fins. When he rubbed his hand over the scales at that part of his tail, though, they felt oddly… clean.

Harry hummed in confusion and shook his head to clear it. He felt heavy and weighed down. He couldn't bring himself to try to sleep, though - not while he knew Ginny was out there somewhere in danger.

He swam sluggishly up to a coral shelf a few dozen feet high in the Entrance hall. There were several anemones on it, housing some tiny orange fish that buried themselves into the squishy-looking tendrils of the sea plant when they spotted Harry. Harry ignored them and sank over the top of the shelf, the anemones brushing against his side, his tail floating off the back edge. Harry hooked his arms around a lump of coral to try to stay steady on the shelf and turned his face towards the glass, determined to keep an eye on things still.

A strange chime rang through the water.

Harry forced his closed eye open and realized he'd fallen asleep. Hours had passed. He couldn't remember seeing anything other than students outside the tank, but he -

The chime sounded again.

Harry's muscles finally seemed to come back to life after his sleep, and he darted off of the coral shelf to shelter beneath it. The sound was coming from the top of the tank. Harry only had a moment to wonder what it could mean before something sharp pierced his gums behind his teeth and pulled.

Harry shouted as his body was yanked from under the coral shelf and dragged upward. He scrabbled at his mouth but felt nothing either outside or in. But the pressure there, and the pain, was not imaginary; and whatever it was was pulling him towards the top of the tank inexorably.

Harry fought. He twisted his body, trying to slow his ascent. After a few moments of struggling he managed to get his tail up high enough to try swimming against the pull, which did seem to have an effect. Harry actually managed to stall, though the mouth pain grew into something tearing and raw for his efforts. Harry gritted his teeth and strained even harder, beating his tail with as much power as he could muster, and felt something give. His body lurched back downward. He swore his mouth should have tasted like blood, but there was still no physical evidence of the pain there.

It was magic, obviously. The fact that it seemed to be some sort of invisible fishing line and hook, and that it was working on him, was something Harry didn't particularly want to contemplate the meaning of at the moment.

Whoever was controlling the spell redoubled their efforts, and Harry's body was jerked back up. He continued to fight, but it seemed that his earlier success must have been thanks to him catching the spell-caster off-guard. He thrashed and fought and even tried clinging on to the rock shelves, but the invisible hook felt like it was going to rip the teeth from his mouth and his hands always lost their grip against the never-ending pressure of the magic.

Harry found himself dragged up to the very top of the tank, where the metal grate he'd been trapped by earlier no longer obstructed his passage. It had split into wedges which were now folded down against the tank walls. Above, Harry saw the vague shapes of several faces peering into the water.

No.

Harry lurched to the side and managed to wrap his finger around one of the metal grates. His grip on it was better than it had been on the rocks. The invisible line tugged and strained agonizingly behind Harry's teeth, but he clenched his jaw and refused to let go. He pushed his tongue against the painful spot, reminding himself that there was no hook and he wasn't actually being injured. It helped, only a little. His grunts and groans of pain escaped as wild curlicues of sound pinging around the water.

The humans above moved, gesturing with arms and shifting in dissatisfaction. The metal under Harry's hands groaned and jerked. Harry redoubled his grip, only to realize that the metal pieces were being drawn upwards to reform the barrier. Only this time, they were trying to get Harry on the other side of it. The metal was pulling his body with it, sweeping him up toward the surface of the tank. If he didn't move, his tail would be crushed between the wedges of the grate.

Harry let go, sweeping his tail away from the closing metal, and made a dash for the center of the grate in a futile hope of escape. The magic he'd been battling yanked him up as soon as he let go, though, and Harry could only reach as the opening closed beneath him.

He heard voices above him, but the sounds were too indistinct this deep. Harry thrashed as the magic drew him up to the surface, close enough that his movements threw water into the air. And above the sounds of violent splashing was a voice.

"-never quite realize how large they are until you get one up close. This one's quite agitated, of course, but he'll tire out soon enough and you'll all be able to see a bit better. Truly magnificent creatures - perhaps I can move him over to the interaction tank so you all can see him properly - "

The speaker was a man with graying hair and a neatly trimmed beard wearing some sort of goggles. The man had his wand out, held over the surface of the water. His grip on it was white-knuckled as if it was an effort to keep it there.

Harry pivoted just under the surface of the water (the pressure anchored in his mouth was no longer pulling him up, but was keeping him from diving down) and then launched himself up into the air towards the wizard.

Harry heard screams and the man flinched back.

But Harry slammed face-first into an invisible shield of magic before making contact, and was rebounded back into the water with a splash.

"Not to worry, the shield will hold strong," the man said above, looking out across the tank.

Well, if Harry couldn't get to him that way, then he had one more weapon to try.

This time, singing with magic was easy. Harry's hate for the man was hot, enflamed by the continued pain in his mouth. His song had no words, not for this tormentor, but he felt his magic reach out with eagerly grasping, bloodthirsty fingers.

"As I predicted, he's trying to drown me now," the man above said, while Harry's magic crashed against a wall of magic above the tank. Harry grit his teeth and kept going, and his magic spread out, seeking any weaknesses in the barrier.

"Singing is usually a siren's first offense. They are ambush predators who stay beneath the waves and trap the unwary with their voices before a seafarer or swimmer has a chance to even realize the danger they are in. Of course, this tactic rarely fails. Very few can resist a siren's call worming its way into their ears."

Harry's magic wasn't finding an exit. The barrier extended over the entirety of the tank, seemingly sewn into the edge of the glass walls.

"However, an enraged siren, or a siren that has already been spotted, will often attempt a physical assault even on uncharmed victims. They are capable of launching themselves great heights out of the water, especially if they have the depth to build up speed before they break the surface. They have been known to jump so high that they can tackle a seafarer straight off the deck of a great galleon - that's a very large boat with multiple stories, not a coin - and drag their victim off the opposite side of the deck into the water. Never let a siren get a hold of you. They have long claws that can dig into flesh, meant to keep slippery prey from escaping, and their teeth will have you bleeding out in moments. You see, the moment they stop singing, their pretense of civilization falls away to reveal the violent savagery at their cores."

Harry had stopped trying to force his magic past the barrier by now, though anger and frustration and hatred still hummed in his gills. The wizard's magic still had a grip on him, keeping his head just below the water's surface and underneath the man's wand tip. What was this? Harry had expected to be dragged out of the water completely. He'd expected to see Voldemort up here, smiling sadistically, with some new torment in mind. Instead, there was this idiot with a magical fishing pole, giving… a lecture?

"Observe the change in the sound of the singing," the man was saying now. "If the barrier was down, you would have felt the magical effects just a moment ago. The sounds he is making now are not ensnaring, but rather, expressions of feeling. Can anyone tell me what they think the melody is communicating right now?"

"It's pretty easy to see that he's pissed beyond reason at you, Professor."

Harry tried to yank his head around to look, only to be pulled up short by the magical line. That sounded like Seamus.

Harry mentally swore.

This was a class. And his former classmates were the students.

Harry renewed his struggles against the invisible tether. This was the chance he'd wanted. If he could only find a way to make them understand him, he could warn them about Voldemort's plans. He could tell them Ginny was in trouble.

But he needed freedom from this dratted fishing hook first!

He won a slight bit of slack as the professor's arm, having slackened since Harry had ceased struggling before, jerked. The professor rallied quickly, though, and tugged the line back up. Harry swore out loud as his face was pulled from the water, his mouth feeling like it had been torn open with a large, bloody gash. There was still no actual injury, though.

"Let me down, you absolute tosser!" Harry shouted, voice coming as a nails-on-chalkboard screech thanks to his mouth being above water. The professor winced. Sweat was beaded on his brow - was that from the effort of dragging Harry up?

"Yes, I think the interaction tank would be best," the man said, panting slightly, before letting Harry's head dunk back underwater. "That will force him to settle down. This one isn't used to being handled, so I expect he'll be rather difficult for a good while. Back away from the tank, please, until I've gotten him transferred."

Harry fought as the man dragged him across to the other side of the tank with his wand. Even as he writhed and pulled, though, he identified many of the faces backing away from the edge of the tank. Most of the Gryffindors were there: Seamus, Dean, Neville, and Lavender. A few Hufflepuffs: Hannah Abbott, Sally-Anne Perks, and Ernie MacMillan. From Ravenclaw: Padma Patil, Steven Cornfoot, Fey Dunbar, Terry Boot, and Anthony Goldstein. And from Slytherin: Pansy Parkinson, Millicent Bullstrode, Vincent Crabbe, and Gregory Goyle.

No Malfoy. He must have dropped the class, whatever class it was. DADA?

Harry processed all this as he was pulled by his head into a shallow extension of the tank. The water was just deep enough to reach up his sides, without fully covering him. Harry's body dragged against the smooth bottom, and his thrashing caused the narrow glass sides to ring from impact. It was barely wide enough to fit him; even more cramped than the tanks Voldemort had used to move him around. The pain in his mouth increased, not just from Harry's struggles, but also because of the drastically increased drag of Harry's body weight against the tank floor.

The professor pulled Harry all the way into the extension, frowning in concentration as he manipulated the spell. A flick of his wand dismissed the magic, freeing Harry's abused mouth. Before Harry could think of taking advantage of it, he heard a metal grate clang into place behind his tail. When he tried to lunge up, he was met with the same impassible magic barrier that was over the rest of the tank. His confines were no bigger than a mer-length coffin.

Harry looked over his shoulder (head scraping against the magic above) and could barely see the metal grate he'd heard blocking the only way out behind him. His arms were crunched up by his head, elbows knocking against the glass. Trying to shift his body weight leaned his hips (hip?) against the walls. The fin running down his spine was tense and trying to stick upright, but was kept down by the magical barrier so that Harry couldn't forget how cramped he was. Harry hissed, sizzling the water, and glared hatefully at the man who'd put him here. His mouth was throbbing.

"There, settle down," the man said towards Harry, crouching slightly to bring his face level with Harry's. Harry hissed at him, baring his teeth, and the man chuckled.

"I'll get you a snack to help make up for it, how about that?" the man said.

…What?

The professor moved away to a row of cabinets along one wall with a counter set underneath. There was a tin bucket on the counter, and the man reached inside, paying great attention to whatever the contents were for a moment.

"Beautiful creatures, aren't they?" the man said as he fiddled with the bucket. "Though as I've already noted, very dangerous. Does anybody know a siren's classification?"

"Class XXXXX magical beast," Millicent Bulstrode answered.

"Correct! You should all know by now what that means, but who can tell me?"

"Class XXXXX beasts are known wizard-killers," Padma Patil said. "They're the most dangerous creatures we know of."

"Correct, Miss Patil. To put it in perspective for you, some other class XXXXX magical beasts are werewolves, lethifolds, and dragons."

They seriously thought Harry was as dangerous as a dragon? Harry had fought one of those, and it had been far more difficult than it seemed to be for Voldemort and his lackeys to smack mer-ified Harry around.

The man finally pulled his arm, dripping wet, out of the bucket. His hand was clenched around something. He came back towards Harry and smiled when Harry hissed at him again. Voldemort had smiled when Harry was angry, too, but it had been a shark's smile - all teeth and sadism, without the slightest trace of true happiness. This was different. Strange. The man smiled as if he was genuinely fond of Harry. Something about the entire situation wasn't adding up, and it made a shiver go down Harry's spine.

"Here you are," the professor said, holding his hand over the tank near Harry's head. His hand opened, and something small dropped through the magical barrier into the tank with a wet plop.

A baby octopus, perhaps a little smaller than Harry's palm, swam into the corner of the glass in front of Harry's face.

"Perhaps that will make you a little less cranky, eh?" the man said, turning away from Harry to confront his class again.

If that man thought that a baby ball of slimy tentacles could put Harry in a better mood after he'd been magically fished up, and after witnessing his girlfriend/ex-girlfriend chased down by mean-looking professors and possible death eaters, then he was delusional. Harry snagged the baby creature and tried to throw it back out of the tank, but he was rebounded once again by the barrier. Was it one-way, then?

The motion turned his face towards where the students were gathered, though, and Harry's shame returned. Friends and former DA members - people who had been counting on him - were now staring at him trapped in a tiny tank, at the mercy of Voldemort and this stupid man with his octopus. He'd let them all down.

Harry shook his head. The professor was talking about something - mer diet, maybe, as fish seemed to come up a lot - but the very people Harry had been hoping to contact were watching Harry. He needed to find a way to talk to them. His own failures couldn't matter more than that.

Harry made himself look at the students standing just a dozen or so feet from him. Really look, without thinking so much about himself.

He was surprised, then, to see that many of them looked upset.

And… more than that… uncomfortable?

Almost no one was standing still. Postures were shifting rapidly as they adjusted their weight, crossed their arms and then uncrossed them again, stuck their hands in their pockets, then moved again to adjust their robes. Almost nobody was looking at Harry's face. Many of them actually seemed to be looking below Harry, at the base of the tank which held him at waist-height for the humans. Some were staring rigidly at the professor, using him like a lifeline so they didn't have to be confronted with Harry, changed.

Pansy Parkinson was one of those who wasn't afraid to look at Harry. Her eyes moved between him and the professor, and she seemed to be smirking.

Harry bared his teeth. She was probably following in Draco's footsteps, well on her way to being a Death Eater. He'd have to be careful about what she saw, then, but she wasn't of any use to him.

And what if the professor caught Harry trying to communicate? Was he a Death Eater? Would he crucio Harry right away, or would he wait until the students had been made to leave? For now, his back was turned. Whatever Harry was going to do, he needed to do it before the man's attention shifted back.

Harry scanned the faces of the DA members again and was surprised when a pair of eyes he hadn't been expecting caught his own and held them.

Neville?

Hadn't he been terrified?

Harry glanced at the professor, then back to his former roommate. Neville was still watching him, steady, without a hint of fear. If anything, he looked determined and stubborn, and so unlike the timid Neville that Harry was used to, that Harry was almost convinced it wasn't Neville at all.

Harry glanced one more time at the professor, then shifted his cramped arms to bring his fingertips against the glass. He checked Parkinson, and waited for her eyes to flick back to the professor.

Then, as quickly as he could, he wrote an invisible, backward "hi" on the glass.

Neville stiffened and glanced between the Slytherins and the professor. Then he slowly shifted his hand to rest on his thigh and drew his finger on his leg in what must have been letters, too. It took Harry a moment to realize it was a "hi" as well, just upside-down and backward from his perspective.

Elation swept out of Harry in an unfettered, upwards scale of notes.

"Oh, now that was unexpected!" the professor said, already pivoting towards Harry.

Harry was already grabbing for the baby octopus that had settled in the corner just behind Harry's head. He knocked his elbow against the glass in his haste, but managed to cram the creature into his mouth and turn back around, sucking tentacles past his lips, in time for the professor to think Harry's sound of happiness was caused by the food.

The octopus was squirming. Harry saw many of the human students making expressions of disgust, but the creature didn't taste bad. It was trying to break out of his mouth, though. Harry chomped on its tentacles to free it, then swallowed the sweet wriggly mass down in a gulp.

"That's disgusting," Ernie MacMillan was complaining, turning to the side.

Harry could still feel it writhing in his stomach. It was ticklish.

The professor was laughing.

"Liked that, did you?" he asked Harry. "Students, I hope you were paying attention! Sirens are very vocal creatures, but we wizards rarely hear their more pleasant vocalizations! What you just heard was a siren expressing happiness! Isn't it incredible how much the sound can fill you up until you feel like your heart will burst with joy?"

Some were nodding slightly, wide-eyed now. Harry cautiously looked back toward Neville and saw the remains of a queasy expression on the other boy's face. Neville met Harry's eyes again, though. A glance at the professor, and then he mouthed, 'really?'

Harry shrugged. He didn't want the professor to be suspicious of the reason for Harry's happiness, since Harry had been careless enough to let it out. And, truthfully, the octopus had actually been really good. The sensation of it in his stomach made him want to giggle. He twitched, trying to repress another uncontrolled sound trying to come out, and sent a sheepish expression at his old roommate.

Neville sent a small smile back.

Harry's traitorous body hummed.

He almost couldn't bring himself to care. The professor thought Harry simply adored octopi. But the truth was, Harry had thought that he was utterly alone and had just found out that he wasn't.

He still had a friend.

"Does anybody want to give him another treat?" the professor asked, drawing Harry's attention back sharply. He was already crossing to the bucket he'd gotten the octopus from.

Treat?!

There didn't seem to be any volunteers, though. The professor actually seemed to pout.

"Come now, this is the opportunity of a lifetime! Very few witches and wizards ever even get to see a siren, certainly not without being eaten!"

Harry thought that that might be exactly why the students didn't seem very keen on approaching, though. Crabbe and Goyle were looking at each other, as if trying to figure out if they should volunteer, and Terry Boot looked like he was trying to drum up some hidden reserves of courage.

"I'll give it a go," Neville said, stepping forward.

Harry's eyes snapped to him, and he lifted his lip. Neville shot him a look that said 'go with it' while the professor happily rambled about Gryffindor courage and lifetime opportunities.

As the professor approached, holding the bucket and looking like Christmas had come early, the nature of this class slammed down on Harry like a giant's foot.

The professor's attitude was just like Hagrid, unable to help himself from loving dragons and acromantulas and from breeding illegal blast-ended skrewts. Except it wasn't Harry's friend standing there crooning, and Harry was the one trapped in the animal pen. This was Care of Magical Creatures, and Harry was the class's current monster pet.

He hardly had time to process that before the professor and Neville were standing over him, their shadows casting him in dim light. Harry was stuck on his stomach looking up at them from the corners of his eyes. He bucked up against the magical barrier, tail sending waves rocking back and forth in the small tank and making the magic sizzle. The professor put a steadying hand on Neville's shoulder, and Harry hissed at the man, spitting water up to hit the glass above the waterline.

"Don't worry, Mr. Longbottom, you're quite safe," the professor was saying. "He can't reach past the barrier. This is an ideal setup for dealing with a siren, but in a more… cost-efficient working space, the first thing you would check would be your deafening charms to immunize you against the song. You would likely have the siren sedated, or strapped down in water of sufficient depth to keep it breathing, as you see we've done here. The water should always cover the gills and be deep enough for them to keep their face under, you see there? The touch of air elsewhere is uncomfortable for them, but not lethal. The next thing you would check would be the tail and arms. You don't want the creature lunging up at you, or able to knock you into the tank using its tail. The tails are incredibly flexible, so you should never assume you're out of reach, even if you're standing by the creature's head."

Neville was nodding nervously, but his eyes were drilling into Harry. What was he playing at?

Harry didn't like them standing over him, though, and besides, even if he might trust Neville not to hurt him, he most certainly did not trust the professor-probably-a-death-eater. And Neville was just going along with him. Why?

"Aside from your own safety, you also must keep a siren - or any mer - secure for its safety. They have a tendency to throw themselves out of the water in fits of aggression. If they are not tended, they often trap themselves in the open air and suffocate."

Harry wondered just how many imprisoned mer the professor had dealt with, to be lecturing like that. He peeled his lips back again, ignoring Neville and focusing on the professor.

"Now, just reach in here and get one - yes, it may take a moment, they're slippery little things!"

Harry's chest was thrumming with warning, he realized. He didn't bother to quiet it.

"There you go! Now, you're just going to hold it out over the tank - yes, right there near his head so it can drop into the water and not his back - yes, right there… Alright, now let it go…"

The octopus had stuck itself to Neville's hand. Neville was squirming, looking a moment away from shaking the clinging creature off.

"Ah yes, you can pry it off, sometimes it takes a bit. Just make sure you don't move past the barrier on the top of the tank."

Neville fought with the tiny octopus for a minute before he finally made it drop. It slapped into Harry's left shoulder, off-target. Harry hissed, feeling the little thing suctioning its way down his back towards his tail, making its getaway where he couldn't reach to get it.

"Ah yes, a bit off-center," the professor said. "Perhaps using a stick would be a bit easier for you, Mr. Longbottom - and it will get our boy used to human interaction! Here-" The professor summoned a forked, metallic stick from the cabinets that looked a lot like what people roasted marshmallows on. "Get yourself another octopus and just let it wrap around those tongues, here."

Neville did as instructed, glancing nervously at Harry as he went. After a minute he'd gotten an octopus to stick itself to the fork.

"Wonderful! Now, the barrier is one-way, so you can just - carefully - lower the octopus on the end of the stick down in front of his mouth. Don't be surprised if he thrashes a bit - he doesn't know what it is, but he'll get used to it in time. He may try to bite it, so keep a firm grip. But remember, he doesn't have enough room to really gain any momentum, so you should be able to handle it."

"Oh, I don't know, do I?" Harry spat, sending angry notes stabbing into the air above.

"Go on, Mr. Longbottom. See if he'll take it. He may not, since he's been getting riled up watching us so near him."

"It would be nice if he trusted me," Neville said, with obviously false levity.

Harry glared at him.

Neville smiled tightly, making eye contact, and lowered the tip of the fork into the water in front of Harry's face. The octopus clung onto the tines, and slid upwards, rotating itself to hide behind the metal bar of the fork.

What was the bloody point of this?

Neville was giving Harry a Look, though, so he obviously had something in mind.

With a pointed hiss, Harry plucked the octopus away from the fork, waved it a little at the two wizards, and then swallowed it down whole while staring Neville down.

Neville made a face, but the professor clapped in excitement.

"Well done, Mr. Longbottom! Well done indeed! I daresay he might even come to like you given some time!"

Neville shot Harry another pointed look.

"Will we be having more lessons on sirens then, Sir?"

"Just one more for this class, I'm afraid… but, if you're interested in further research, you could join the Aquatic Research Program."

The what?

"And when will that be meeting, Sir?"

"Just a moment, Mr. Longbottom." The professor turned to address the rest of the class. "The rest of class time will be spent making an anatomical drawing of a siren. Please make sure to label all external body parts and organs, including the various fins. You'll find references for the body parts on page forty-two of The Oceanic Wilds. Don't copy the drawing you'll find there, as it isn't highly realistic, as I'm sure you'll see."

The rest of the students moved past Harry's tank, to where long tables and benches were set up, to set up their drawing supplies. The professor turned back to Neville.

"To answer your question, Mr. Longbotttom, the program will be meeting mostly on Saturday mornings, though it won't be every week. It will depend on the current studies and tests being conducted, you understand. Are you interested, Mr. Longbottom? I daresay you might have a knack for the beasts, but I had thought that the familiar face of this one might put you off."

Neville glanced at Harry, but then set his gaze firmly back on the professor. "It's strange, Professor, yes - but it's like you said at the start of class, and I realize that I won't get another opportunity like this. If it's alright, I'd like to be involved in the program."

What had the professor said at the start of class?

"Bravo! I'll have to confer with the Headmaster. I'll send you an owl once that's sorted."

"Oh, er… the Headmaster doesn't like me much, Professor."

"That's nothing that should stand in between a student and achievement! I'll talk to him personally, Mr. Longbottom."

"Thank you, Professor."

Neville shot a small smile at Harry, then moved away to join the rest of the students.

Harry endured being a live model for the rest of the class. The professor walked around the room, offering advice on the drawings and alternatively coming to cast some sort of monitoring charm over Harry. Harry glared at him every time, wishing he could at least splash the man, but the professor continued to show fondness for Harry no matter how murderous Harry tried to appear.

In between, Harry tried to wrap his mind around everything he'd overheard. Neville wasn't terrified of Harry as Harry had thought. Most others were. Neville had some sort of plan that involved Harry being a Good Little Siren and the Aquatic Research Program. That sounded decidedly ominous, especially since Harry had to assume that he would be the subject of the "studies" and "tests" involved. And it seemed that the professor believed that Harry was actually an animal. And perhaps he'd told that to the entire class, which could be why no one else had acknowledged the fact that he was Harry.

It wasn't exactly all great news, but Harry tried to force himself to see the bright side. He'd thought that he was alone, trying to figure out a way to talk to his friends in Hogwarts by himself. But it looked like Neville was, probably, working on the same problem from the other side. If Neville was able to get into that… research program… he'd probably get a lot more chances to make contact with Harry. Perhaps they could even figure out a way to pass messages.

It was a start. Harry doubted that writing backward messages on the glass without any ink was going to cut it for detailed communication, and it would take far too long to manage it around other people without being found out.

"Please hand in your drawings, class! Before next week, write four feet on the differences between the species of saltwater mer, and three feet on proper safety precautions needed - and why - for handling sirens!"

The students got up with some subdued grumbles about the homework, though Harry saw many of them still watching him. He wasn't able to keep track of them as the professor came back towards the tank, wand out. Harry showed his teeth.

"I know, I know, you've been very patient," the professor sighed. "Not to worry, almost time to let you go. I'm just going to run a few quick scans while I've got you."

Not all the students had left. Neville was lingering near the door, and the professor noticed just before he went to cast something with his wand.

"Mr. Longbottom. Can I help you with something else?"

"I was just curious, Professor. I don't have another class after this; might I stay and watch?"

"Ah, certainly! You'll need to cast a deafening charm on yourself, though - do you know it?"

"Yes, Sir."

"Excellent. Stay at the edges of the room - I'm going to have to let our boy here up, and I don't want him lunging for you - and go ahead and cast the spell on yourself. Make sure it's nice and strong. I can't do much for you if he lures you into the water, you understand?"

"Yes, Sir."

Neville shot Harry an apologetic look when the professor turned away, but cast the charm on himself and stood back, watching.

The professor spent a moment washing Harry in light, tingling magic that probed into Harry's innards uncomfortably. Harry fidgeted in his confines, chest warbling warnings.

"All done," the professor said, the magic fading. Then he turned his wand on himself. "Deafenti."

The man backed away to the wall, then looked over to Neville. Neville gave the professor a thumbs-up.

The professor muttered something under his breath and wove his wand through the air. Harry felt the magical barrier over him disappear with an almost audible pop, letting his spinal fin free. At the same time, the gate at his tail disappeared.

So he was being let go, back into his greater prison. Harry was both relieved and annoyed – the first because he had been stuffed in a box for well over an hour, and the second because the fact that he was relieved to go back to what was effectively a prison cell was shameful.

He didn't have other options, though. As much as he'd like to leave the tank and give the professor a piece of his mind, it was impossible at this distance. He pushed against the wall near his head, trying to push himself backward despite the drag caused by the shallow water. He stopped almost immediately when the movement of the water into his gills suddenly made him feel as if he were choking.

Okaaaay, so swimming backward was a thing he hadn't done so far for a reason.

Annoyed, Harry levered himself up out of the water entirely, wincing as the water streamed out of his gills and air stabbed in instead. He crawled over the top of his own tail, his stomach feeling compressed at the harsh twist of his body. It took a moment before he was far enough to pull his tail out from under his body, straightening out and finally able to sink his gills back under the water's surface. He paused at the lip of the main tank and glanced at Neville. The other boy was watching, frowning. Despite Harry's annoyance and confusion, he really hoped Neville's plan worked out.

Harry finally shoved himself off of the ledge of the shallow tank and fulled submerged once again with a relieved, pulsing hum. As he dove past the released metal gate and felt the pressure of the water overhead grow, he allowed himself to indulge in the deceitful sense of safety the depths brought.

A/N: If anyone has ever actually eaten a live, baby octopus, I'd love to hear what it actually feels like. My descriptions are total conjecture.