The Son of the Dog Star

Later that afternoon, after Potions…

Cassian and Blaise were walking toward the Slytherin common room when Cassian noticed Luna trailing behind, her usual dreamy expression clouded by unease.

His eyes caught something odd—Luna's left shoe was scuffed, and the right one looked suspiciously loose, as if it had been tugged off.

"Hey, Luna," Cassian called gently. "Everything all right?"

Luna looked up, her silvery eyes blinking slowly. "Oh, hello, Cassian. It's just… I think the nargles have been especially mischievous today."

Cassian raised an eyebrow.

"My shoe vanished in the corridors earlier," she continued with a small, whimsical smile. "I'm certain it wasn't a student—nargles adore tricks like that near the Ravenclaw tower."

He frowned but said nothing. Luna tucked her book under one arm and sighed.

"And Professor Umbridge's class is tomorrow," she said, tone growing wary. "It's supposed to be dreadful. No real magic, just endless rules and lessons about following orders. She's so horrid. I've bet she's being influenced by some unpleasant creature—something that makes her want to make everything as strict and joyless as possible. Personally, I suspect the wrackspurts. Dreadful little creatures."

Cassian replied, confused, "That sounds… awful."

"Oh, it will be," Luna agreed softly. "But I have a plan. I think I can handle it."

Cassian managed a small smile. "Well, if you need me, just come find me."

Luna beamed. "Thank you, Cassian. That's very kind."

With that, she started to skip before she tripped lightly over a loose floor tile and giggled, as if the whole world were one big, puzzling joke.

---

Later in the Slytherin Common Room...

The fire in the hearth hissed quietly, casting green light across the stone walls and polished furniture. A half-dozen Slytherins were scattered about, speaking in low voices or pretending to study. Draco Malfoy sat comfortably near the center, legs stretched out in front of the fire, bragging about something to Crabbe and Goyle, who gave their usual grunts of approval.

Cassian stepped through the entrance, his school bag still hanging off one shoulder.

His eyes locked on Draco.

And then he moved.

No words. No warning.

He dropped the bag as he crossed the room in four sharp strides and drove his fist straight into Draco Malfoy's mouth.

The sound of it—knuckles on bone and the dull crack of contact—snapped the room into silence. Draco fell backward over the arm of the chair, hitting the floor hard as Crabbe and Goyle shot up in confusion.

Cassian didn't give him time to react. He grabbed the front of Draco's robes and hauled him halfway upright—just enough to punch him again, this time straight across the cheek.

Blood sprayed. A tooth hit the stone with a dull tink.

"You think I wouldn't notice?" Cassian growled low, barely audible over the crackling fire. "Sabotaging my potion? In Snape's class?"

Draco spat blood, groaning. "You're mental—!"

Cassian slammed him back to the floor.

Crabbe moved forward.

So did Blaise—calm, smooth, wand already drawn. "Don't," he said simply, voice like ice. "Neither of you has the brains or the reflexes."

Crabbe froze. Goyle looked to Draco, who was now bleeding profusely from the mouth and trying to drag himself away.

Cassian's voice dropped to a whisper, lethal in its restraint.

"Snape's already down my throat," he hissed, "and you thought you could humiliate me for a laugh?"

"Enough, Rookwood."

The voice came from the stairs. A tall, pale-skinned seventh-year prefect had emerged, arms crossed, wand still tucked in his robe. His tone wasn't angry—just tired.

"Unless you want Snape dragging your entire bloodline through the dirt, I suggest you don't get blood on the carpet. Again."

Cassian froze, breathing hard.

The prefect sighed, already turning away. "Handle it. Fine. Settle it. Whatever. But do it quiet, and do it clean. I don't care if Malfoy's chewing soup for a month—just don't make me write a report over it."

Cassian stared down at Draco, who was moaning now, clutching his face with one hand and trying to find his balance.

He let go of Draco's robes, letting him slump to the floor.

Blaise lowered his wand.

"Well," he said lightly, "that was subtle."

Cassian picked up his bag without a word.

Draco groaned, curling on his side. Blood smeared his chin and pooled at the corner of his mouth. No one moved to help him.

Cassian passed Blaise, jaw still tight.

"You feel better?" Blaise asked under his breath.

"No," Cassian muttered. "But I'll sleep better tonight."

"That'll make one of us," Blaise muttered before smiling faintly. "Slytherin therapy. We settle debts in knuckles and wandfire."

"And as long as Snape doesn't see it," Cassian replied, "nobody cares."

They walked upstairs together, leaving a chattering common room and a whimpering Draco in their wake.

---

The fourth-year Slytherin dormitory reflected its two very different occupants. Blaise's side was pristine—polished dark wood, silk sheets embroidered with his family crest, and carefully arranged heirlooms and books. Cassian's corner was simpler: a faded Holyhead Harpies poster above a worn bed, and a few modest but well-cared-for gifts from his mother—a faded wizarding photo, a protective cloth charm, and a wooden music box. Together, the room was a quiet blend of aristocratic refinement and humble resilience.

If it wasn't for Blaise, Cassian wouldn't even have decent robes to wear. He said it was a crime against Slytherin to have Cassian dressed like a Weasley.

Cassian sat at the edge of his bed, sleeves rolled to the elbows, cradling his right hand in his lap. His knuckles were raw and purpling, skin split in one place where it had connected too hard with bone.

He'd cleaned the blood off already, but it still throbbed dully with every heartbeat. A fair price.

If he was being honest, that wasn't entirely about putting Draco in his place. He just happened to be a convenient punching bag to vent his frustrations on about Sirius and Luna.

Did that bother him? Not really.

Blaise sat at his desk across the room, casually flipping through a textbook he clearly wasn't reading. His eyes kept drifting to Cassian's hand.

The silence filled the room until Blaise asked suddenly, "You ever actually seen a nargle?"

Cassian glanced over. "You're thinking about Luna again."

"You're the only one who thinks about Luna. I'm thinking about nargles. Allegedly."

Cassian huffed a laugh and leaned back against his pillows not denying it. "No. Never seen one. She claims they're invisible and attracted to mischief."

"She also claims they hide your shoes and whisper spells into your hair."

Cassian shrugged. "She also says the Thestrals hum when they sleep. I checked. They do."

Blaise turned, eyebrow raised. "You snuck out to the Thestral paddock?"

"Don't pretend you wouldn't do it just to prove her wrong."

Blaise cracked a grin. "Fair point."

He winced slightly as he flexed his bruised fingers, watching the skin stretch painfully.

"Was it worth it?" Blaise asked after a pause.

Cassian didn't answer right away. He looked down at his hand like it belonged to someone else. "He'll think twice next time."

Blaise let out a slow breath and stood. He walked over, reached into his nightstand drawer, and pulled out a small green glass vial.

"Essence of dittany," he said, handing it over. "You'll scar if you leave it like that."

Cassian took it without meeting his eyes. "Thanks."

As he uncorked the vial and began dabbing it carefully on his split knuckle, Blaise settled onto the edge of the bed across from him.

"We can't just let whoever it is bullying Luna off lightly," Blaise said finally.

Cassian's jaw tightened. "No. We find out who it is. Quietly. Carefully."

"And then?"

Cassian's eyes flashed. "Then they'll learn exactly why messing with Luna is the worst mistake they'll ever make."

Blaise smirked. "Sounds like a plan."

Cassian stood, determination settling into his posture. "Tomorrow, we're shadowing Luna. We find out who's behind this."

Blaise raised his cup in a silent toast. "To nargles and justice."

Cassian smirked and reciprocated, "To Justice."