Raylynx's POV

We Apparated to the rock jutting out from the middle of the ocean, only a few hundred feet from the cave.

I looked over at Regulus. He nodded once.

Then, we plunged into the icy cold water and swam across. Regulus helped me get across the rocks. Once we were across, I dried us both off with a flick of my wand.

We made our way to the entrance. I stepped forth and pressed my palms against the solid rock. After a moment of concentrating, I felt tension against my hands. The magic here was resisting me. But why? When I pushed harder, it held its ground.

"I can feel the presence of magical barriers. But I can't figure out what they require," I said, frustrated.

"Knowing the Dark Lord, you'd have to give something up to gain entry," Regulus muttered bitterly. "Like your sanity."

Give something up to gain entry?

"Wait, that's it. Sacrifice," I said. "He would want the enemy to weaken herself in some way."

Suddenly, my mind flashed back to the mission in the sirens' cave, where I was trying to break through the ice with my fist to get to Marlene. I could have sworn it was when my blood hit the surface of the ice that all the magical barriers broke down. Of course, it was probably coincidence. Still, it was worth a try.

"What are you doing?" Regulus asked me fearfully as I pressed the wand tip to my palm.

"Payment," I said grimly as I felt a slash in my hand. I sprinkled my blood across the stone wall. A moment later, an engraving appeared on the rock wall, etching deeper and deeper until it became-

"A door," Regulus said in awe.

I pushed on the door that suddenly appeared in the stone wall, and it opened.

Silently, we both drew our wands. I stepped in first and Regulus came close behind me.

I could hear my own breath. I couldn't see very far. Somehow the darkness in here was denser than normal darkness.

"Raylynx?" Regulus called softly from behind me.

"I'm all right," I said, cautiously stepping forward.

"Shall we risk some light?" Regulus asked. "Lumos!"

Light erupted from the end of his wand.

We both stood still, on guard, in case the presence of light set off any alarms. But there was only stillness and silence.

"Here goes," Regulus muttered. "Be on your guard."

I gripped my wand tighter.

"Lumos Maxima!" A ball of light burst forward from Regulus' wand and illuminated the whole cave.

I held my breath as a pitch-black lake appeared in front of us, completely still, it's dark waters holding yet unknown horrors. Then, a jagged shape emerged from the dark waters.

"There!" I pointed at a small island in the middle of the glass-like lake. "That must be where the Horcrux is. It has to be."

"I agree. But how do we get to it?" Regulus wondered aloud.

"Well, not by swimming, I suppose," I said, trying to peer into the black depths of the lake.

"No, the Dark Lord would have wanted access to it himself," Regulus guessed. "There must be a more elegant way to reach the island."

"Let's search the shore," I suggested.

"Carefully," Regulus said, and I nodded. We split up to search the shore, proceeding with due caution. Then, Regulus said, "Wait, I think I've found something."

I made my way over to his side. Regulus' hand was wrapped around something and he slowly tapped his wand over his fist. I gasped as a post materialized in his hand- a post with a chain attached to it. We pulled on the chain together and to our utter awe, saw a small boat rise from the water and float to us, cutting smoothly through the glassy water like a ghost ship.

"I suppose this is our way across," Regulus said quietly, and I could sense the nerves in his voice.

He carefully got in and then held his hand out for me.

However, the moment I stepped into the boat, it began to sink.

I hurriedly stepped off, back onto shore.

Regulus and I both looked at each other.

"Seems like we can't both ride it," Regulus remarked.

"I'm not letting you go alone," I said firmly, starting to feel afraid.

"Raylynx-"

"I can't. I can't let you go without me."

"We have no other option," Regulus pointed out.

I fell silent, torn.

"Please, trust me," Regulus said quietly. "Let me… Let me make my move."

I stood soundlessly, my heart waging a war with my mind. Finally, I said, "Do you have the fake locket?"

Putting together my extensive research with Kreacher's and Hokey's help, we had determined that the Horcrux was indeed Slytherin's locket. Hokey confirmed that Hepzibah's greatest treasures were Hufflepuff's Cup and Slytherin's locket, and Kreacher had testified to seeing a locket on a silver chain. From there, Regulus and I had made a replica of Slytherin's locket to replace the real Horcrux.

Regulus nodded and patted his chest pocket.

"All right then," he said, and swallowing hard, he turned away from me.

As soon as he did, the boat began to move across the surface of the lake.

I watched half in relief and half in terror.

He was a little less than halfway across, when he called out my name suddenly.

"Raylynx," Regulus said, and his voice was frightened.

"What?" I said immediately, tensing the grip on my wand. I was ready to protect him at whatever cost. "What is it?"

"I think… I think there are dead bodies in the water. I see pale faces." Regulus swallowed. "I swear I saw one move."

Cold sweat broke out on my palms. I knew what they were.

"Inferi," I said, trying to hide the nervousness in my voice. "They must be Inferi."

"But you're all right," I added quickly. "They've let us raise the boat. We must be doing okay."

Regulus was silent the whole way across. Finally, his boat hit the island with a small bump and I saw him rise out of the boat and step onto the island.

I raised my wand, terrified the Inferi would strike, but everything was calm.

Regulus stepped forward towards what appeared to be a chunk of stone in the center of the island.

"It's… It's a sort-of basin. It's filled with liquid," he called back to me.

A liquid?

I saw him raise his wand and try to Vanish it or siphon it away. He tried multiple variations of all sorts of spells. Finally, I heard him say softly, "It must be drunk."

"Reg?" I called out to him, starting to panic. We shouldn't have separated. We shouldn't have separated.

"It has to be drunk," Regulus repeated. His voice was almost resigned.

"Regulus, stop," I said weakly. "Stop now. Come back. We'll have to try again another time. This is too risky."

"I can't," Regulus said. "If I try to go back, the Inferi will know I'm not him. I have to drink the potion."

"No! What if it hurts you?"

"I can take it," Regulus said grimly. "I can withstand it."

"Regulus, come back!" I called out. But even as I prayed my voice would reach him and persuade him to turn back, I already knew it was impossible. He was right: the Inferi would devour his boat as soon as he tried to head back without touching the Horcrux.

Regulus took a small white object and scooped up whatever liquid was inside the basin. He raised the cup or shell to his lips.

I held my breath.

He tipped it back into his mouth and swallowed.

Suddenly, he coughed.

"Regulus…" I said warningly.

He scooped up more potion, drank again, and then went into a hacking fit.

"Regulus," I called, louder.

"No…. No…" Regulus said. I could see his left hand balled in a tight fist. He was shaking his head back and forth, slowly.

"Regulus! Stop drinking! Get away from the Potion!" I called across to him.

Regulus shivered as he lifted another shellful of the potion and emptied the contents in his mouth. His whole body started trembling badly. He started murmuring to himself, "No, no, no, no!"

"Regulus!" I cried out. Frustration was eating away at me. I would have given anything to be on that island, to wrench that shell away from him and throw it into the Lake.

Regulus' shaking hand tipped another shellful of potion into his mouth.

Suddenly, he started shouting, "Leave Sirius alone! Leave him alone! Just leave us alone, please!"

"Regulus!" I shouted again, louder this time. "Regulus, it's an illusion! Whatever you're seeing, it's not real!"

I could hear Regulus' sobs across the lake. "W-We didn't do anything. We didn't- What did we do? What did we do that was so wrong? We didn't ask to be born. We're your children. You should have wanted us... You should have- have-!"

"Regulus, please! Hear me!" I shouted. My heart felt like it was being eaten by acid. I couldn't bear this feeling of being stranded across the lake, unable to help him in any way.

Regulus swallowed another shellful of the potion.

He started to make strange gurgling sounds amidst his crying and his body was being wracked by terrible spasms and pains. "Sirius, Andy, help me! Please, anyone help me! Please. PLEASE!" He shouted, and the sound was raw and intense.

I watched him self-destruct, alone on that god-forsaken island.

Still, he managed to fight the illusions and was conscious enough to tip another shellful of potion in his mouth.

Then, he opened his mouth- and he screamed. It was a terrible scream, so sharp and piercing that I had to cover my ears. The wretched sobs that followed afterwards broke me and I started to sob too.

Regulus screamed for a long time, though he still somehow managed to scoop the last of the potion out of the basin. But he was possessed- wrenching the shell away from his mouth and painfully dragging it to his lips and then wrenching it away again.

I heard his ragged voice saying, "Last one, last one" and then he said to himself in a hideous voice, "You deserve this pain, you murderer." He drank the last remnants of the potion, and then he collapsed on the rock, utterly silent.

"NO!" I screamed. "NO, NO, REGULUS, PLEASE!"

"ENNERVATE! ENNERVATE!" I threw spells at him, praying that he would wake.

He was silent for another minute and I started to put my wand in my teeth so I could risk swimming across when he coughed.

My breath caught. I squinted and saw his body shiver against the rock. Then, he turned over and coughed hoarsely.

Thank Merlin! I thought. Thank Merlin. My head felt light-headed with relief.

I heard him say, "…Thirsty… So… so thirsty…"

He started to move towards the water- but I thought I saw a hand- he reached for the lake water- "REGULUS, DON'T-!"

Cold, clammy hands of a corpse shot out of the dark water and dragged him under, headfirst.

"REGULUS!" I screamed so loudly that my voice echoed in the cavern.

I couldn't risk an offensive spell- what if I hit Regulus instead?

I tried hard to think of what I knew about Inferi- Seymour's voice rang out in my head. "Their weakness is fire."

"Incendio Stella Linus Aqua Impervius!" I risked a spell I would never have been able to perform before. Please, Wand of Kings, help me! Show me your power.

Five streaks of fire burst from the end of my wand and dove into the water, speeding towards where Regulus was surrounded by Inferi.

A second later, his head broke the surface of the water and he gasped for air.

"Regulus!" I called, dropping to my knees and holding out my arm. "Swim towards me, I'll cover you!"

I waved my wand again, producing more fire to clear the way for him.

But the sheer amount of Inferi was overwhelming.

I knew that by the time Regulus finally reached the shore, we would not have enough time to run out of the cavern.

I frantically looked behind me, searching for the exit. The old opening was long since gone.

I spotted another opening, some ways ahead. There was a sea gate above it, waiting to come down, and I could see a straight drop to the ocean.

Regulus, panting, was almost to me now. I waved my wand once more to fend off the Inferi, swimming in horrible jerky movements towards Regulus. I threw caution to the wind and pushing myself back onto my feet, I stepped into the water to help Regulus onto the shore.

He was pale, shivering, and gasping for air. But even as I managed to pull him to his feet, hands erupted from the dark water and grabbed at our ankles.

"Incendio!" I shouted again, and the fire that shot from my wand whipped their hands away from us.

"Lean on me!" I shouted to Regulus and he did. We rushed towards the Seagate exit together, but even now, ghastly shapes were emerging from the water in hordes. It was horrifying. I wanted to shut my eyes to avoid seeing the Inferi, but I knew that we had to make it out.

"Come on, come on," I encouraged Regulus, whose breathing was getting fainter and fainter. I could tell that he was still struggling to make sense of what was reality and what was illusion. His eyes were unfocused and he wasn't really seeing me.

"I just didn't want Sirius to be hurt again…" Regulus murmured, confused. "I didn't hate him… I never hated him. But if I agreed with him, they'd just hurt him more. And then, there were my parents. I just... I wanted them to love me. That's all. I swear I never meant to hurt anyone... I swear..."

"I know, Regulus, I know. But we've got to move forward, okay? We have to get out of here!"

We were halfway there when I saw an Inferi's arm snatch Regulus' shoulder.

"Impedimenta!" I yelled, pointing my wand over my shoulder and the Inferi was slammed backwards, into another cold, wet corpse body.

Regulus was starting to awaken, his movements were less sluggish and we were making fast progress towards the exit. But not fast enough.

A clammy hand shot over my mouth. I screamed and gagged as cold fingers forced their way into my mouth. I tried to point my wand, but it was directly behind me-

"Impedimenta!"

Regulus' voice rang out loudly and the hand disappeared.

Gagging and gasping, I tried to compose myself as we continued hurrying towards the exit.

They were right on our heels, literally.

I wanted to scream in terror, but even that was a waste of time. We ran together, hastily throwing spells over our shoulders whenever we could catch a breath.

By the time we reached the gate, Regulus was fully in the present, though of course, it all seemed too much like a nightmare to be true.

Suddenly, Regulus stopped as though something had occurred to him.

"Regulus, what are you waiting for? Incendio! Come on!" I tried to tug him out of the exit, but he wouldn't budge.

"Only one," he murmured. "The gate will sense how many… Like the boat."

"Incendio! Impedimenta! Regulus, come on!" I begged desperately. The Inferi were starting to pile up and crowd around us.

I tried to push Regulus forward. But suddenly, he turned, grabbed me by the waist, and threw me forward. I flew through the air and past the exit.

CLANG!

The sea gate came crashing down and then this hellish nightmare became even worse, for Regulus was captured on the other side.

"REGULUS!" I scrambled to my feet and slammed myself against the gate.

"Go, save yourself!" he shouted.

"Impedimenta!" I blasted five of the hundreds of Inferi that were converging onto him.

"Don't wait for me! Go!" Regulus yelled.

"INCENDIO MAXIMA!" I screamed.

The intense burst of magical silver fire kept them at bay for a long time while he shook the gate with all his strength and tried multiple Blasting spells on it, but even with the Wand of Kings, the fire was reaching its limit, and I could only keep going for so long. I still could not produce Gubraithian Fire. That was gold magic, the magic that only the the likes of Merlin had mastered and which even Dumbledore could only produce with time.

Regulus' eyes met mine and he saw my power fading in my eyes. I produced another blast of fire, but weaker this time.

He suddenly smiled at me gently and that frightened me more than anything because it signaled his willingness to accept his horrific situation.

"It's all right," he told me gently.

I started sobbing and my hand grasped at the bars separating us. My focus kept the flames from disappearing, but even so they were beginning to weaken more and more. The Inferi were almost able to step through the wall of fire now. They were almost able to reach us.

"No..." I pleaded. Please, let me be stronger. Please, let me save him!

Regulus' hand, stained with blood and dirt, gently covered mine.

"It's all right," he repeated.

I whimpered when the fire began to die out and the Inferi were multiplying again. Their hands were reaching for Regulus, insisting that he follow them to their watery grave. Regulus look at me with kind eyes. He knew what was coming. So did I. But I wouldn't have it. I wouldn't let this happen while I was still alive.

I took a deep breath and concentrated all my magical power. Then, I shouted loudly once more, "INCENDIUS MAXIMA!"

A giant wall of flames appeared behind Regulus yet again, preventing the Inferi from getting to him. Regulus turned to me in the little time I'd bought us.

Before he could say anything, I burst into tears.

"Regulus," I whispered, tears streaking down my face.

Struggling a little, Regulus reached his hand through the bars and gently stroked my face, wiping away the tears.

"Ray," he murmured softly. "Will you tell my brother that I love him? And that I'm sorry. I know you can't tell him right away, but someday... When I'm gone and the two of you find time together... Tell him he's always meant everything to me, in this insane world of ours..."

The flames began to die out.

"Reg…"

"I love you," he said earnestly and suddenly his expression was that honest, open, slightly nervous expression I'd fallen in love with so many times. He even smiled for a minute, though he looked confused and his eyes weren't quit rid of the internal struggle between panic and acceptance.

He pressed his hand against the gate. "Here, take it. Keep it safe until you figure out how to destroy it." He passed me the locket from behind the bars. "We made our move," he said proudly. But the pride had a finality to it.

"Regulus," I cried out, reaching for him.

Our hands met and he squeezed my hands tightly in his. Our foreheads met in the space between the bars.

"I love you, Raylynx, " he said again.

"I love you, too!" I said desperately. "Regulus, I love you."

He smiled and said peacefully, "I know."

But once again, we both knew my love was not going to be enough. It never is.

"I'm… going," he mouthed the words slowly and I could read the fear in his eyes.

I shook my head but he braced himself, closed his eyes, and then came the hands- the dead, clammy, slick, gripping hands.

"NO! REGULUS! REGULUS!"

I refused to let go of his hands but they pulled him from me.

"Incendio! Incendio!" I shrieked wildly, but there were so many of them, dragging him into the water.

"No, Reg- You can't- INCENDIO!"

"Leave!" he screamed at me, "Leave, you fool!"

"Regulus!"

He was halfway into the water… out of my grasp.

"NO, REGULUS!" I screamed for him, sobbing, crying, and shrieking.

But he was gone now- just a bubble.

And the Inferi were beginning to crawl towards me, stacking themselves against the sea gate.

Barely able to keep my head on straight, I backed away, tripping onto the ground.

Unable to remember how to Apparate and hating everything to do with magic, I jumped off the cliff. I saw the ocean at a great lengths below and half hoped to drown, but knowing the locket in my hand gave me a reason to live. To the very end, Regulus was clever, knowing exactly how to move me. I couldn't die so long as this Horcrux was in my hand. Because it was our move, together. He had passed it onto me, and it was my turn to complete our move against Voldemort.

SLAM! The plunge into the water was so long that when I finally hit the water, it felt like I'd smashed into a solid wall of steel. Everything broke inside me. It felt like my lungs had been compressed and smashed. I lost all sense of thought and feeling other than the overwhelming sense of being crushed. My whole body contracted as the water was icy cold, and the current pushed me down, down, down, out of the reach of even light.

But at least in the short time I was in the water, I was one with him.

Regulus, I love you. It's not the way you wanted. I'm sorry. And it was never, ever enough. I'm sorry for that, too. But you and I, we had the same soul, right up until the very end.

I lost consciousness when the waves were still far above me.