Dedicated to Hannah, who also loves all things Regulus. Sorry for splitting up the Black Brother Tragedy. It's canon.
There were four of them. They were lying in the dark, in wait. The dungeon was alive the way a forest is alive; with low, autonomous sounds that seemed to have no origin and got no immediate attention. They were looking back and forth between each other, just waiting for a victim.
.ooo.
A boy in a black cloak trimmed with green and silver was humming as he walked down the dungeon corridor.
It wasn't a relaxed hum, the merry kind you'd sometimes hear from Hufflepuffs in the sun, the kind that sounded more like purring than anything else; the notes were strained and perfectly on time─an eldritch tune, haunting and morosely beautiful.
Regulus, occupied by everything and nothing at all, didn't notice the crying at first. The sobs mixed with his own melodious sounds, and for a moment, he felt as if they came from himself.
When he finally realised they were something else, something set apart, he felt almost as if he'd lost a part of himself. The tune died on his lips, and the boy looked around, trying to pinpoint the origin. In the dungeons, everything echoed, ricocheting off the damp walls. Voices grew louder while words were muffled, and Regulus thought the sobs might have been meant for understanding (like hurried prayers on broken tongues), but he couldn't.
Choosing a general direction, he stalked towards an entrance to one of the dungeons, lingering with his ear against the door. A part of him hesitated; curiosity killed the cat, and he wouldn't know what to say if he was noticed.
In the end, however, instinctive kindness and a hunger to know made him turn the doorknob and push inside.
The sobs stopped immediately.
Nothing awaited him inside; the room was desolate, almost windswept, as if he'd stepped into a moor or a marsh. The already cold dungeon seemed to drop a few degrees, and Regulus hugged himself.
"H-hello?" he called into the empty room. Taking a few steps forward, he suddenly heard something slam behind him.
Regulus startled and turned around. Behind him, the door he'd opened a second ago was now closed, its stubborn smack still ringing in his ears.
"Peeves?" Regulus called, wincing when his voice rose into a high pitch. "Peeves, I know it's you; you're the only poltergeist here."
Although, he'd never heard Peeves sound like a woman before. Peeves always showed himself, too, because he loved the look on people's faces when they knew the culprit but couldn't do anything about it.
As if in response to his call, laughter suddenly rose, full of malice and ice.
Regulus spun on his heel and grabbed the doorknob.
It wouldn't budge.
"Let me out, let me out!" he screeched, his twelve-year-old voice cracking painfully in his ears. His body betrayed him, wanted him to cry, but Regulus, determined now, took out his wand and cast Alohomora. It was probably just wizards, it was probably just wizards, it was probably just older students and magic, and─the door wouldn't budge.
"Alohomora!" he cried again and again.
The door wouldn't budge.
Spinning around, Regulus heard the scrambling sounds of wood against stone, seeing chairs intermingle like a gambler's cups.
No hands were holding them.
"Regulus Arcturus Black," a disembodied voice started booming as quick, lithe footsteps made up the chorus, "You have walked into my domain. You have set me free."
It wasn't until one the invisible footsteps seemed to stop right in front of him that Regulus realised how little he'd been scared before. Reaching out with his hands, he tried to swipe at the air, hoping for something solid. At one point, he thought he heard a thump, but he still couldn't see anything.
He only managed a few spells in blind directions before the voice continued. "You shall be the first sacrifice."
"Nooooo!" he shrieked, holding his hands to his ears and backing up against the wall. Helplessness overwhelmed him, and he slipped down the door to a sitting position, still shouting and crying.
Not until a hand shook him and pried away one of his hands did he realise that his nightmare was over.
Before he opened his eyes, he heard uncontrollable laughter, desperate and hungry, like a group of boys egging each other on. When he finally did open them, it was Sirius that stood before him.
"S-Sirius?" Regulus asked, confused. "What are you doing here?"
Sirius, having a hard time forcing out words in between laughs and gasps of air, finally answered, "It was us all along, Reg! We were the ones who did all this."
Then, almost as an afterthought, he looked to one of his friends (the one with the glasses; they were always together, Regulus remembered, and something started burning inside of him) and said, "You should have seen your face."
The two of them, barely containing themselves until now, burst out laughing again, and the echoes of the four boys' howls haunted Regulus almost as much as the disembodied voice and the footsteps.
"But my Alohomora didn't work. H-how did you do that?" Regulus asked with a hint of accusation.
Sirius, oblivious and giggling, answered, "Peter's a half-blood, so he taught us some Muggle tricks. Wasn't it brilliant?!"
"No!" Regulus exclaimed "No, it wasn't! It was childish and─and─" Looking around at Sirius' friends with a mixture of anger and helplessness, he noticed that the short one had a big grin on his face while the one with glasses was shaking with subdued giggles. The third one met his gaze, his eyebrows knitting before he looked away.
In front of him, his brother's face fell, and Sirius sneered, "You're exactly like them."
Regulus was paralysed. His heart started beating, and a lump formed in his throat. A part of him was afraid it was made of tears. "Like who?"
"Mum and Dad," Sirius answered.
It was as if Regulus had been doused with ice water. "What do you mean?"
His entire body tensed in anticipation of Sirius' answer. He didn't want to hear it; it would just be another blow, another slap to the face.
"You're just as condescending, just as pureb-looded─" the last word was drawn out, and for a second, Regulus thought Sirius sounded like Severus, "─Perfect Little Regulus."
Now, the others in the room had stopped laughing. In fact, Regulus was almost certain they'd stopped breathing, but he didn't dare to look. Sirius was towering over him, his body strung with hostility, every muscle tight with the adrenaline of the fight.
For the first time in his life, Regulus hoped he would never be like his big brother.
"You scared me!" Regulus shouted, angrily. "And it wasn't funny!"
The temperature in the room fell again, this time for real. In front of him, Sirius put up a barrier that Regulus was sorry to realise he recognised.
"Come on, Prongs," he said, looking at all three of the boys. "Let's not waste anymore time here."
Behind him, Regulus saw Sirius' friends exchange glances before shuffling towards the door, which now opened without complaint.
"You know, little brother," Sirius, his upper body twisting in the doorway, "it's a shame. If you'd been a little better at taking a prank, I might have invited you to do some with us."
Sirius left, both the room and his brother in devastation.
Prompts
The Mystery Competition: Regulus Black, genre: suspense and/or angst
The Game Is On: The Sign of Four - Write about any of the Marauders
The Fairy Tales Challenge: The Boy Who Cried Wolf - Write about a prank gone horribly wrong
Additional prompts: Beautiful Crime by Tamer
Challenge Your Versality: Angst