Regulus anxiously paced around in his room, thinking hard about what Kreacher had told him a week prior about the events that took place when the Dark Lord had required an elf. With his suspicions high, Regulus told Kreacher to not speak to anyone about it and to make himself as scarce as possible. He tried to make sense of what Kreacher had told him. There was a cave by the sea that led to an underground lake. In the middle of the lake was an island that held a torturous potion and a locket, but what did the locket have to do with this?
Regulus stopped his pacing for a moment and thought. A locket. That triggered another thought that he had heard from his cousin Bellatrix in passing about the Dark Lord giving her an object to put in the Lestrange vault. As he stood in the middle of his room, curiously pondering the facts that lingered before him, he suddenly turned on his heel, looked at his black walnut colored desk, and gave it a pleading look, as if it would provide him an explanation.
Regulus suddenly remembered that he had received a book from his cousin right after he returned home for the holidays, and he quickly began to rummage around in his desk for it. He hoped beyond hope that he was wrong. He had to be. Finally finding the book that he was looking for, he opened it cautiously with a distasteful look upon his face. In the dim-lit room, he pulled out the leather bound book - Secrets of the Darkest Art - and without hesitation began to flick through its pages. Finally finding what he was looking for, Regulus sat down in the desk chair and read quietly, his face falling with every sentence that his eyes passed over.
When he finished, he realized that his suspicions were confirmed. The Dark Lord had accomplished in making at least two Horcruxes. Regulus stood, terrified at the thought of what his discovery meant. It all made sense now. The Dark Lord, who was always a shroud of mystery with an ever-changing appearance, who had a thirst for power and yet was ultimately terrified of death itself. He also knew that if anyone had ever found out that he, Regulus, knew about the two objects he would be dead.
Thinking long into the night, he came up with a plan. He found a locket that used to be his mother's, transformed it to look like the one Kreacher had described to him and gathered up a piece of parchment. He hastily scribbled a note and reread through his note with his eyes ending on his initials; R.A.B. He gathered up the note, stuck it into the locket, put the book into his trunk and left the room. He moved briskly towards the kitchen, looking for Kreacher, a wild look in his eye.
“Kreacher!” Regulus called out.
At the end of the kitchen, a small door opened, and Kreacher walked out of the cupboard with a curious look on his face. When he saw Regulus, his facial expression changed to one of deep concern.
“Kreacher,” Regulus said quickly, “I need you to take me to the cave tonight.”
Kreacher took Regulus’s hand, and, with a simple crack, they left Number 12’s kitchen behind.
An eerie moon hung high above the sea as Regulus and Kreacher arrived at the mouth of the cave. The waves struck the rock walls with such blunt force that it sent sea spray into the sky, causing it to dance around like jewels in the moonlight.
They walked into the dark cave's mouth, Regulus muttered ‘Lumos’
and began to look around. The walls were damp and etched away from wear and tear of the sea. Kreacher walked him over to where the Dark Lord forced him to give blood as passage. Regulus cut his hand gingerly, placed it onto the rock where Kreacher indicated and watched as the wall melted and crumbled away. Before stepping foot into the cave, Regulus looked back to the opening towards the sea, and with a heavy heart, he took one final step forward knowing he would never see the sea again.
As they entered the cavern beyond, they walked slowly and carefully on the rock-strewn shore. Regulus could see that the cavern was large and, as he knew from what Kreacher told him, filled with a trapped, underground black lake. Ahead of him, Kreacher stopped suddenly. Regulus halted immediately as Kreacher pointed down at the water and spoke in a croaky whisper, “This is where the boat should be.”
Regulus nodded and walked forward. He placed his hand out like Kreacher had instructed that the Dark Lord had done and he waited concentrating hard. His heart jumped in his chest and seemed to echo throughout the cavern. Suddenly, there was a rippling disturbance in the water, and a chain flew into Regulus’s hand. Catching it, he began to pull in a ghostly-looking, green-lit boat.
As the boat reached the shore, Kreacher and Regulus stepped inside. At once the boat drifted lazily across the water's mirror-like surface. Sometime later when the boat reached the island in the middle, it shuttered to a halt.
Disembarking from the boat, Regulus and Kreacher stood on the tiny island. Together they walked over to the basin and saw inside a potion, and beneath a large, golden locket.
Regulus sighed a heavy breath, knowing that in order to make this work he would have to be the one to drink the potion. He could not, in good conscious, allow Kreacher to go through that torture again. Turning to look at Kreacher's horrified face, Regulus knelt down.
“Kreacher,” he began quietly, “I am going to take the first drink of this potion myself. I am not sure what it will do, but I order you to keep making me drink it until it’s gone. When it is” - he looked around at the still water surrounding them - “I want you to do as I ask. Transfer the lockets, go home, and do everything you can to destroy the one you’re going to take from the basin. Do you understand?”
“Yes, Master Regulus,” Kreacher croaked obligingly.
“Oh, and Kreacher.” Regulus turned to look at the elf again. “You're forbidden to tell anyone about this. Especially my parents.”
“Yes, Master Regulus,” Kreacher repeated, looking down at the rock-covered island.
Regulus grabbed the shell sitting on the basins edge and scooped it into the potion. He tried to prepare himself as his hand raised the shell to his lips, and he drank.
The burning pain was agony. Painful memories and thoughts fluttered through his mind.
He was running down the entrance hall of Number 12 Grimmauld Place, chasing after Sirius. Regulus was shouting at him to wait up while Sirius grinned mischievously back and ran faster. Regulus, not watching where he was going, tripped over the troll leg umbrella stand and broke his left arm.
Kreacher gave Regulus more of the potion, and the memory changed.
He was seeing his mother's hurt and angry reaction to Sirius leaving home and burning him off of the family tree. How displeased she would be if she found out what Regulus was doing at that moment. He would be an outcast. The Dark Lord would surely go after his parents for doing this, and it pained him to know that they might die over his change of heart.
Kreacher again gave Regulus more of the potion, and the memory changed once more.
This time, he was looking at the pained face of Sirius, who was trying to get Regulus to understand that the "pureblood mania" wasn’t worth it. He didn’t have to go through with what was expected from him. Sirius was there to support him. When Regulus declined and refused, calling Sirius a "blood traitor," Sirius’s face had a look of pain no brother should ever have to see.
Kreacher kept giving Regulus the potion, as he'd been ordered to, and each time the memories would change and the burning pain would ensue.
When Kreacher forced the last shell-full of potion down the refusing Regulus’s throat, he dropped the shell. Regulus screamed in agonizing pain, and everything went black. When Regulus regained some consciousness in a matter of seconds, he came to the realization that he needed water.
“K-Kreacher,” he muttered, “w-w-water.”
Kreacher walked quickly to the water's edge to scoop up a shell-full of cool water. The elf, knowing what was going to happen, moved quicker. He knelt down besides Regulus and allowed him to take a drink of water. Dropping the shell as he had heard movement, Kreacher rushed to the basin just as a hand reached up out of the water in front of him. He quickly grabbed the heavy gold locket, and switched it with a replica, and left, as Regulus had told him to go home.
Regulus was starting to come round when the Inferi approached him as he lay silently on the island. His movements were slow and achy as he reached for his wand. Gripping the handle as tightly as possible, he began to fire curses at as many of the now-swarming Inferi as he could. They just kept coming out of the water, faster than he could cast spells.
Because of the growing number of Inferi and his delayed reaction time, Regulus was caught off guard when an Inferius grabbed him around the ankle, with it's vice-like grip. As the Inferius began to tug on his ankle, Regulus slipped and lost his balance, causing his wand to fly up and into the water.
His eyes were wide, and he knew that these were his final moments. As he physically fought with everything that he had in him, images swam through his mind. His parents, and how upset they would be, losing another son when he never returned home. Sirius, his brother, who he wished could tell him that he was right and that he had finally changed his mind. As his feet touched the water, he was brought back to reality. He struggled until his body was waist- deep into the water. All the fight in him had left him now. He was pulled further into the lake, and as his head reached the water, he took one large, last breath. His mind began to race as it filled itself with its last thoughts. He wasn’t a coward- he was brave, and here he was, going to die the unknown hero. As he finished his thought, the light had left the once vibrant, eager eyes and Regulus had died, at peace with the final act he had chosen.