Harry stayed tense, on alert, for at least an hour, but nothing changed in the office. Harry was alone, in the dark, without a sound to betray someone nearby, and only the hungry dragon in the painting to keep him company.

Satisfied that he was going to be left alone for awhile, he set to examining his tank. He probed at every corner and every edge. He slammed himself against the glass to see if it would crack. He wriggled his hands out into the room, pinched between the upper edge of the tank's glass and the paneled ceiling of his cage, and tried to shove at the glass. When that didn't work, he twisted his hands painfully to claw at the weaker wood above the wall of the tank instead. He heard his nails leave scratches in the dark paneling, but no matter how he twisted and tore at it, he couldn't do any true damage. He tried one last time to create an exit, aiming this time for the wood paneling directly above the water, even though if he was successful in ripping a hole in the ceiling it likely wouldn't get him anywhere.

In the end, all he had to show for his efforts were pale gouges in the finely polished wood, and a few small splinters floating in the water. Harry sank to the bottom of the tank, staring at his pitiful handiwork through silver ripples above. Something was bubbling in his chest; a pressure, growing, no matter how he tried to swallow it back…

"Help," he whimpered. The quiet trill echoed hauntingly between the walls of glass and sounded out into the room, lonely in the silence.

The bubble in Harry's chest exploded.

"Help!" Harry screamed, surging up to press his mouth near to the crack between the glass and the ceiling without leaving the water. "Help me! Someone! I need to get out! Help me!"

What should have been shrill screams emerged as a harrowed, staccato melody, impossibly beautiful despite its frenetic fearfulness. Harry choked on it, abruptly stopping the inadvertent song, hating that his voice sounded unearthly and melodic when it should be ragged and scratched.

He gulped water desperately and dug his nails sharply against his arms, grounding himself in the stinging pain of it. Pain was the same as it had always been. It was real, it matched what he knew of reality, unlike every sound that came from his mouth and the water moving through his body and the gentle swish of his large tail fin against the smooth bottom of the tank. He dug his nails in deeper until he had to grit his teeth, but it was better than feeling that overwhelming panic.

What had all his efforts to get out been for, anyway? Even if he could get out of the tank, what could he do? Drag himself hand over hand to the door before he suffocated?

The silence of the room was deafening. The darkness seemed to press in on him, though Harry noted with dim comprehension that he could still make out writing on the spines of books and the delicate scrolling shapes of the sconces.

Part of him wished that Voldemort would come back. Seeing his enemy made Harry angry, and feeling angry was far, far better than this lonely, helpless fear.

Harry curled at the bottom of the tank, eyes heavy, shuddering in barely averted panic and exhaustion combined. The water pressed down on him with a comforting weight, moving gently over his skin and through his throat and gills. It must be night. Harry couldn't figure out how long it had been since he'd been running through the forest, trying to escape the snatchers with Hermione and Ron. Had it only been a few hours? A day? Two?

At least they're safe.

Harry's mind loosened slowly until it felt as if he were floating, his body moving gently back and forth in the slight currents caused by his rippling fins. His thoughts began to drift, moving so slowly that it was impossible to track one thought transitioning to another.

One…eye…closed…?

He was too tired to wonder about it further.

He didn't sleep. Hours passed in silence, his body still and relaxed, his mind sluggish, but he never faded into dark oblivion. Without conscious effort, one eye remained open for a time, before it would close and the other would open instead. He felt strangely half-asleep; aware, yet barely so; something in his mind dictated that the fins along each side of his tail ripple in movement just as it seemed he couldn't make both eyes stay closed at once.

New… sleep?

Time no longer existed. Fear no longer existed. He was pleasantly heavy, weighed down, thoughts so slowed that panic and fear and anger didn't have the strength to push through the thick syrupy feeling in his mind. Water flowed evenly through his mouth and gills, a reassuring, steady stream. His body bumped lightly against the wall of the tank, limp enough that the slight movements of the water had nudged him into the corner.

Stay… like… this.

Of course, he couldn't. He saw the door to the office open through his left eye, and a pulse in his scar sent an electric jolt through his mind and body. His heart rate picked up speed, his muscles twitched into alertness, and he dragged his right eye open as the lights in the office flared to life with a wave of Voldemort's wand.

Harry blinked, rattling the cobwebs from his brain as if he'd actually been asleep. Had an entire night passed?

He certainly felt more rested than before, and his stomach was growling.

Voldemort wasn't alone. His pet snake was wound around his body and over his shoulders, thick with muscle and long enough that her tail trailed near his ankles. He moved as if unaffected by her massive weight, though, closing the door neatly behind him before extending a hand towards the ground so she could slither down to the floor.

Harry rose in the water unthinkingly, his anxiety and fear from the night before returning. He gritted his teeth; he was supposed to be angry, to be strong. It was harder to feel that way now, though, with the scratches on the paneling above testifying to how very trapped he was.

Voldemort looked up as Nagini detached from him completely and made eye contact with Harry. His smile was quick and sharp.

"Couldn't find a way out, I see," he said, darkly amused.

Something cornered and feral rose in Harry's throat. He swallowed saltwater and glared.

"Ah, and you had the entire night to find a way," Voldemort sighed, as if disappointed. "It looks as if you gave it your best effort, though. It seems siren claws are surprisingly sharp."

Harry scowled. He didn't have claws, he had… elongated, sharp, thick, fingernails. Not claws. Not claws.

His scar was pulsing and throbbing, but… there was something else, tickling at the sixth sense he'd been learning to listen to over the last few months. His eyes drifted towards Nagini, and he frowned. His head was ringing. As if…

"Nagini is here to determine your fate, Harry," Voldemort said conversationally. "We shall see whether the effort to capture and keep you has been worth it. If not…" his expression sharpened, his smile growing into a feral grin, "you may want to brace yourself for a very, very painful end."

Death threats were something Harry understood. He wrenched his eyes back to Voldemort, and that feral thing hiding in the back of Harry's throat ripped free in a savage hiss that made the water around him buzz with hatred.

Voldemort stepped closer, leaning towards the tank with an almost curious look in his eyes. "How interesting. One day, and already adopting inhuman expression. Tut, tut, Harry. I had thought you'd at least try to hold on to the pathetic amount of wizardly dignity you possessed."

Harry's fins stood on end. He set his jaw, pouring all his hatred out through his glare.

That sixth sense didn't stop prickling. There was a horcrux in the room, and it had come in with Voldemort.

"I suppose exhortation to behave yourself is pointless?"

Harry yanked his attention back to the dark wizard in front of him and glowered, tamping down another wild hiss. He couldn't fully focus, though. He felt a pull towards the other end of the tank, closer to where Nagini was basking in the heat of the fire…

"Very well. Beastly behavior is the best we can hope for, from one such as you."

…Nagini was a horcrux.

Harry didn't have time to process his shock at the revelation. Voldemort shrunk the tank's dimensions with a quick motion of his wand, trapping Harry in a shallow pool just large enough to contain him. Harry tried to blink away his shock and shoved up, lunging out of the water to aim a swipe at Voldemort's black robes, but Voldemort stepped neatly backward to avoid it and only clicked his tongue disapprovingly.

"Foolish. Know when you have lost, and bow to the might of magic."

A flick of the man's wand lifted Harry straight out of the water. Harry screeched as the air knifed into his body, and he squirmed in the magic's grip as the little water remaining in his gills quickly drained from his sides. Harry aimed another desperate swipe toward Voldemort, but the man was out of reach, smirking at Harry's struggles.

"How does it feel, Harry?" Voldemort asked teasingly. "Is it not frightening to be so dependent on a bit of water? In the ocean, of course, It wouldn't be a problem for you, but here, thirty-odd miles away,saltwater is in such short supply. So… easily controlled."

Harry was already feeling the effects of the lack of water, but Voldemort's taunting had gotten his blood pulsing with anger again, and he enjoyed the strength that came with it.

"Bastard," Harry hissed, enjoying Voldemort's minute wince at the resulting screech.

Voldemort flicked his wand, slamming Harry forcefully against the ceiling before letting him fall to the floor. Harry landed hard despite the slightly cushioning carpet and couldn't help a grunt of pain as his bones were jarred from the force. His vision spun from lack of oxygen, but he saw the shrunken tank set into the wall just a few steps away. He forced himself onto his stomach and levered himself up on shaking arms, his tail twisted behind him. No longer buoyed by water or magic, he felt so unbelievably heavy. It was a monumental effort to drag himself a scant few inches over the carpet, his vision spinning wildly now.

Voldemort stepped next to Harry and clucked his tongue pityingly. "I'm afraid I can't let you back into your prison yet, Harry, though your eagerness is encouraging." The man chuckled as Harry's arms gave out, his vision blackening. Harry was vaguely aware of the evil wizard crouching next to him, and of the hard tip of a wand dragging over the ridges and gaps of his gills and then upwards over his chest and neck to his mouth and nose.

"Bullagus."

Saltwater streamed from Voldemort's wand tip and into Harry's mouth and sinuses. Harry gulped at it, feeling it surge down into his chest and out of his gills, washing away the sting of the air and shoving the darkness in his vision away.

Voldemort stood again and stepped back before Harry could swipe at his feet again.

"Have you realized yet, Harry, that even if you were to obtain a wand again, you would not be able to pronounce the incantations necessary?" Voldemort asked in a soft, threatening purr. "Have you realized that even if you could, your magical core has been transformed into that of a creature? You are… not a wizard, I am afraid."

The words hit harder than Harry would have expected. One of his happiest memories was of Hagrid's visit to that little shack out on the sea, when the half-giant had provided the explanation for all of Harry's strangeness: he was a wizard. Everything had begun to make sense, then. Things that had made him a freak became things that made him special, made him worth something.

He hadn't lost that… had he?

Voldemort smirked, satisfied that his jab had hit its target, and turned away. He moved one of the low coffee tables by the armchairs into the center of the room, then transfigured it into a long, stone table as high as his waist. The spell pushing water through Harry's gills was working independently of Voldemort's wand, now, the water cycling back up to his mouth once it had exited his gills in a shimmering, gravity-defying stream that tickled against Harry's dry skin.

Harry made himself push his torso off the ground and began dragging himself as quietly as he could towards where Nagini lay lounging in the heat of the fire, tongue flickering contentedly. He wasn't sure how a horcrux being alive would complicate destroying one, but it stood to reason that killing Nagini would effectively destroy the horcrux as well, didn't it? If he could just get close enough, he could pierce his nails through her neck, and send another piece of Voldemort's soul to hell despite the unfortunate replacement of his legs by a tail.

"Ah, ah, ah, Harry," Voldemort tutted. Harry yelped as his body was jerked upwards from the floor and sent spinning through the air, past Voldemort, to land with a skull-ringing thud on Voldemort's transfigured table. Harry immediately tried to roll off but found that every part of his body in contact with the stone was glued down by a sticking spell. Even his head was stuck by his hair and a fin-like ear, forcing him to watch Voldemort.

"Nagini," Voldemort hissed. The giant snake lifted her head towards him, tongue flicking out curiously. "Come, investigate the fish-man."

Harry's heart thundered as Nagini slithered towards him. He couldn't help but remember, "Nagini… dinner," and poor Professor Burbage getting eaten whole -

Voldemort levitated the massive snake up and lowered her directly onto Harry. Harry wriggled against Voldemort's restraining magic as Nagini slithered over him, her weight crushing down on his bones painfully. She almost smothered him, heavy coils sliding smoothly over his scales, pushing at his fins as if they were as weak as parchment. He felt her tongue lightly flicking over his skin, smelling, tasting.

He squeezed his eyes shut, trying not to panic at the images of grisly death flashing behind his eyes.

"This one tastes like salt," Nagini hissed. "I do not think I would like him, master."

"Not to eat," Voldemort hissed with an amused chuckle. "Does he feel familiar? Can you sense something with him, as you do with me?"

That confirmed it, she was a horcrux. But… what did he mean? Voldemort didn't think…

"Yesss…." Nagini hissed slowly. "Like master, but… different."

"A brother," Voldemort suggested, and Nagini hissed in agreement.

Harry's stomach dropped. Everything Voldemort had been speaking of suddenly made horrible sense. Pieces started falling into place, things that hadn't quite added up for his entire life. Ollivander, in first year, remarking on the unusual circumstance of Voldemort's and Harry's wands being brothers. Dumbledore, explaining Harry's Parseltongue with his theory that a portion of Voldemort's powers had transferred to Harry. The Sorting Hat, insisting that Harry would have done well in Slytherin.

Even more damning was the connection between Harry and Voldemort's minds. How had no one questioned that? Hermione had wondered why it was that Harry could sense horcruxes, though Harry had chalked it up to their mental connection and thought no further on it.

Voldemort's speeches since Harry's capture suddenly made a lot more sense.

"Brother," Nagini hissed slowly, her tongue flicking over Harry's cheek. Her coils shifted over his chest, moving over his gills and interrupting the stream of water flowing. Harry choked.

"Careful, Nagini," Voldemort cautioned, reaching out to delicately lift Nagini's bulk away from Harry's side. "Do not suffocate your… dear brother." He smiled darkly at the end, his eyes drifting to meet Harry's horror-filled ones. A moment later, his hand trailed lazily up to part Harry's sodden hair away from his forehead, exposing his scar.

Harry tried to wipe the horror off his face. Voldemort didn't know that Harry knew about the horcruxes, and he couldn't know, or else he'd make finding Hermione and Ron his top priority instead of reveling in his capture of Harry.

"You do not want me to eat him?" Nagini hissed, turning her head away from Harry's to look at Voldemort.

"No…" Voldemort flicked his wand, and Harry felt the tightness of the sticking spell vanish. He squirmed, but Nagini's bulk was just as trapping as the magic had been. "We must keep him safe, Nagini."

Nagini ponderously turned herself around over the top of Harry's body, keeping him pinned down the entire time, then shoved her head underneath his tail and began winding her way upwards again, wrapping him slowly in iron coils. He shuddered as she tightened around his chest, pinning his arms to his sides, and then he couldn't help a whimper as her neck wound around his and her tongue flicked over his ear.

"Salt-brother," the massive snake mused, squeezing enough that Harry felt his bones creak. A quiet, high-pitched whine escaped from his chest, and Voldemort chuckled, leaning over Harry's face to drink in Harry's fear.

"You do not deserve the honor," Voldemort said softly, still smiling while Harry struggled vainly against Nagini's crushing weight. "And, believe me, I would kill you in a heartbeat for all the trouble you have caused me, Harry Potter, if Nagini had not sensed a connection to you. I suspected, but now it is confirmed. An accidental Horcrux." Voldemort's voice dropped to a reverent whisper, and Harry froze, not having expected Voldemort to say this much aloud.

"I didn't intend to make you, but the death of your parents would have served as an adequate catalyst…" Voldemort mused. "I was not sure it could be done. My experiment with Nagini went well, but she is an animal, without a soul. But you… a living being with a soul of your own, hosting a part of mine... such a thing is unprecedented."

Something dark inside of Harry pulsed. His scar throbbed, and Nagini shifted her coils around him in the same moment, her scales sliding over his with disconcerting ease. Her touch felt like tendrils of putrid darkness, but to a part of him, it also felt like… home.

Harry's eyes flew wide, and he thrashed, trying vainly to get free of the massive snake. He couldn't even make his sharp fins stand up on end, though, to cut her. Nagini tightened her body around his, momentarily covering his gills so that he choked on still water, forcing him still.

"Safe…" Nagini crooned. "I will keep you safe."

He shuddered, head spinning in unadulterated panic, but gave up his painful struggles. If he'd had lungs still, he would be hyperventilating. As it was, his eyes were blown wide and he could hear his heart galloping in his chest. Disgust and fear rolled through him overwhelmingly, but underneath was a small whisper agreeing with Nagini, welcoming her touch, yearning for her and Voldemort like long-lost family.

"No, no, no," Harry said, eyes darting, fingers wriggling, heedless at this point that Voldemort was still leaning over him, watching, hungrily drinking in the terror he'd caused. "I'm not you, I'm… I'm good, I'm me, I'm not evil, not dark, not… I'm not!"

"How beautiful," Voldemort crooned, dragging his fingernail down Harry's cheek, making Harry scream as his scar lit up in fresh pain. "You've always kept up such a brave face, Harry. If I'd known all I needed to do to see you tremble I would have told you my suspicions sooner. Your denial does sound so painfully haunting in mersong - perhaps I can capture it in a sound crystal through my memory."

Voldemort pulled away, and Harry gulped for breath, trembling, mind-numbed by an overload of adrenaline and emotion. Nagini loosened slightly, hissing pointless assurances in his ear, but her body around his held him relentlessly still.

Something powdery gathered in his eye before it coalesced and fell away. It rolled down his cheek and then Nagini's scales until it clicked against the table, from which Voldemort picked it up and held it up to the light.

"Ah, yet another benefit of keeping you alive. These are valuable potion ingredients - almost impossible to find in natural habitats, and there is only one successful mer farm in the magical world at present, remotely located somewhere in the Pacific. Governments do have a nasty habit of shutting such useful businesses down."

Voldemort tucked the pearly tear away into a pocket in his robe before turning back to Harry and continuing conversationally. "Don't you think it rude to be crying over this, Harry? After all, your life expectancy has increased exponentially. Rejoice."

His grin held all the comfort of a shark's.

"I'd rather die," Harry forced out, the water over his mouth turning the words into a weak, trembling song.

Voldemort hummed quietly and ignored the words he couldn't understand. "I have also made you useful in this form. Scholars have many questions about aquatic magical species and rarely have the opportunity to study them adequately. The last significant study on sirens was done in the fifteen-hundreds and led to the invention of the imperius curse - an incredible magical breakthrough at the time. Just imagine what developments could be made from an extended, modern study backed by recent magical advances, such as sound crystals?

"Magical Britain has, for far too long, been stifled by the Ministry's restrictive policies. I aim to make us respected leaders of the magical world once again, and you will play a part in that, Harry."

Harry tensed as Voldemort reached out to draw his finger lightly over the slashes of Harry's gills, and hissed in pain as his scar burned in response. Voldemort smirked, and the pain spiked - Harry slammed his eyes closed in an effort not to scream.

"Another question to be answered," Voldemort purred. A moment later his hand withdrew, and Harry could think again. "Why does my presence cause you such pain? Nagini is perfectly content in my presence, yet the horcrux in your scar seems to delight in tormenting its host. Is it because my soul clashes with yours, and is strengthened by proximity to the original soul piece? Or is my hatred of you broadcast through the soul connection, and my soul translates that hatred into inflicted punishment?"

Suddenly, Voldemort slapped his hand over Harry's forehead, splitting Harry's mind with agony. Harry screamed, arching against Nagini's constraints, trying to fight off the pulsing darkness with thoughts of his friends, of love, but all he felt was pain and burning and all he heard was his own pitched, piercing scream -

Voldemort withdrew, but he was smirking, and Harry was trembling and dizzy.

"Do not fight, salt-brother," Nagini advised, flicking her tongue gently against his cheek as another pearlescent tear formed and dropped to the table. "Master takes care of what is his."

"Leave me alone," Harry hissed, just able to see her thick coils over his chest. He had to close his eyes, to try to push away the pounding in his head, to try to suppress the part of him that was relishing in Nagini's closeness – the same part that seemed to be reaching out to Voldemort like a toddler reaching for a parent. He held Hermione and Ron's faces in his mind, determined to keep it all at bay -

"Salt-brother can speak?" Nagini hissed curiously, and Harry froze as a fresh wave of horror swept over him. If Nagini understood, then…

"Harry," Voldemort hissed, smiling slowly. "It seems I won't have to go without your endearing insults after all."