The summons arrived under the laboratory door like a quiet threat.
Cream parchment. No flourish.
Technical Council — 10 a.m. — Headmistress's Office.
I washed my hands longer than necessary. The cold water numbed my fingers. It helped. I adjusted my cuffs until they sat perfectly, then left before I could stall.
Hogwarts was louder this morning. Life trying to prove itself. Students flooding corridors, robes swishing, voices bouncing off stone. The castle carried it all with a kind of stubborn pride.
It still hummed wrong beneath it. A pressure behind my eyes. A thin, constant pull under my breastbone. As if the walls were listening for an argument.
McGonagall's office smelled of ink and smoke. The windows were cracked open; winter air sharpened everything.
They were already gathered.
Flitwick small and alert, hands folded. Sprout solid, sleeves rolled, dirt under her nails like evidence she still believed in growing things. A few others I recognised by posture more than face.
Cassian Vale stood by the bookshelf, Ministry grey cut too neatly to belong in this castle. Calm. Polished. Watching.
Snape sat at the far end of the table. Black robes, high collar, spine straight like a rule. Hands clasped. Pale knuckles. A man built of restraint and spiteful survival.
He didn't look at me when I entered.
McGonagall did. "Ms. Vane. Sit."
Not a courtesy. A placement. The chair she indicated wasn't at the edge.
I sat, case by my heel, palms flat on the table. My breathing stayed steady. I refused to give the room any visible leverage.
McGonagall tapped her wand. A map unfurled across the table: Hogwarts' wards, corridors, bleed lines inked in red like veins.
The precision in the runes tightened my throat.
His hand.
He'd been doing this without me. He'd been keeping the castle upright while I stayed away and called it wisdom.
"The anomalies are recurring," McGonagall said. "Escalating."
Flitwick nodded. "They feel responsive. As if anticipating us."
Sprout's eyes narrowed. "Or being guided."
Cassian's smile arrived softly. "The Ministry agrees. Which is why we're here to ensure a stabilisation plan is enacted."
I watched him instead of reacting. His voice didn't press. It invited. It made control sound like care.
Cassian set a folder on the table and opened it with deliberate calm. "A containment lattice. High-risk nodes reinforced. Reactive residue extracted and secured."
The diagrams were elegant. Symmetrical. Beautiful in the way cages were beautiful.
My stomach tightened.
"You'll fracture it," I said.
Cassian's eyes warmed, as if I'd offered him something interesting. "Or we prevent it from fracturing itself."
"It isn't doing this to itself," I said. "The misalignments are intentional."
"An assumption," he replied.
"An assessment."
"You're too close to this," Cassian said, gentle enough to pass for concern.
My spine went rigid. The words hit my body first. Heat under my ribs. Breath catching, then forced smooth again.
Too close. Emotional. Clouded.
The same shape. Different mouth.
"I'm close enough to notice what you're skipping," I said.
Cassian didn't flinch. "We're discussing risk. You have a history here."
The room tightened around that sentence. Something hollowed out beneath my ribs. Even the fire seemed to hold.
McGonagall's gaze sharpened. "Mr. Vale."
Cassian lifted a hand in polite apology and kept going anyway. "Personal tensions have been documented. Hogwarts responds to pressure. It's reasonable to consider catalysts."
Reasonable. Sensible. Safe.
The words I'd once swallowed like medicine.
I kept my face still. "Your plan treats the castle as property. It's a living structure with memory. If you extract residue with force, it discharges. It doesn't disappear."
Cassian's smile thinned. "Then we reinforce containment."
"More pressure," I said. "More pushback."
McGonagall's voice cut sharp. "Severus. Speak."
Snape lifted his eyes.
Not to me. To the map.
"Vale's lattice ignores the fault lines beneath the north wing," he said. Flat. Precise.
"Anchoring there will create a shear point."
Cassian's brows rose slightly. "Then we adjust."
"No," Snape said. One word. Clean. Final. "You cannot adjust what you refuse to understand."
His gaze flicked to me quick, assessing....then away. Acknowledgment of competence. Nothing else.
He respected my work.
He didn't defend me.
The silence tasted like punishment.
Cassian's voice slid back in. "Then we reduce variables. Restrict movement. Curfews. Close corridors. Relocate students temporarily."
Sprout stiffened. "You mean lock them up."
Cassian's hands spread. "I mean prevent casualties."
McGonagall's mouth tightened. "Hogwarts is not a prison."
The castle groaned. Low. Deep. A sound from the stone itself.
The candles flickered.
Then the lights went out.
Not dimmed. Gone.
Darkness dropped like a physical thing. Cold slapped the back of my neck. The fire died with a strangled hiss. Pressure rolled through the air, thick as wet cloth, pushing at my ribs.
Pain flashed behind my sternum, sharp and brief.
Someone sucked in a breath too fast.
Snape moved.
I didn't see it. I felt the shift in space, his body cutting between me and the table. Heat off his sleeve close to my arm without contact.
"Do not move," he said, low.
Not comfort. Control. Instinct.
Wandlight flared in trembling points as McGonagall and others cast Lumos. Faces reappeared, pale. Cassian stood as if darkness bored him.
The map was wrong.
The red lines were crawling outward, bleeding across parchment, seeking new paths.
"It's feeding," I said.
"On what?" Flitwick's voice shook.
"On tension," I said. "On conflict."
Cassian watched the map like he was watching a demonstration. "Remarkable."
Snape snapped a counter-charm. Cold air rippled. The red ink halted, shivering back into stillness.
McGonagall's voice was clipped. "This meeting is over. Now."
Chairs scraped. Staff moved quickly, murmuring. The room emptied in controlled urgency.
Cassian waited until the last of them left, then turned to me as if this were the natural next step. "Ms. Vane. A word."
"I'm occupied," I said.
"You'll want to hear this," he replied, still mild.
He led me to the window alcove. Winter air sharpened the silence. He stood angled toward me, hands behind his back, posture open enough to feel safe.
Persuasion always dressed itself like safety.
"This reaction," Cassian said, "is not typical residue behaviour. It's amplification."
"Provocation," I said.
He held my gaze. "By you."
My body went still. Cold settled in my gut.
"I'm not causing it," I said.
"I'm saying you're a variable you can't control." His voice stayed soft. "Hogwarts responds to unresolved bonds. Unfinished conflict. You are entangled."
"And your solution," I said, "is to isolate me."
"My solution is to protect you," he replied, seamless. "Resources. Authority. Ward archives you don't have. Personnel. Leverage. And one simple truth: Severus Snape is a risk factor."
The name sounded clinical in his mouth.
My chest tightened. "You don't know him."
"I know patterns," Cassian said. "And I know you're too intelligent to ignore evidence because it's uncomfortable."
Too close. Emotion clouds perception.
Same blade. New handle.
Behind him, in the corridor, a shadow shifted.
Snape stood half out of sight, posture rigid, black against stone. He didn't interrupt. He didn't step in. He watched with the cold stillness of a man refusing to be baited.
My pulse jumped anyway. Heat rose under my ribs, quick and humiliating.
Cassian's smile flickered as if he'd noted it. "He watches."
"So do you," I said.
"I watch because it's my job," Cassian replied. "He watches because you are a problem he doesn't know how to solve."
Snape didn't deny it.
Cassian's voice softened further, almost kind. "You don't have to repeat the past. You left once because it was sensible. Safer. People persuaded you for your own good. Don't make the same mistake in reverse."
My skin went cold.
He didn't need Lily's name. He didn't need to say it. He knew exactly where to press.
Cassian slipped a folded paper from his sleeve and held it out. "Access codes. Ministry ward archive. Use them or don't. But understand: pride will not keep this school standing."
I didn't take it.
He tucked it away without offense, as if refusal was just another step in the sequence. "Consider what happens when your history becomes a structural flaw."
He nodded once, polite, and left.
Snape stepped into the alcove after a beat.
He didn't come close. He held distance like it was law.
"You entertained him," he said.
"I didn't," I replied.
"He wanted something."
"So do you," I said, and hated how my breath tightened on the last word.
A tendon jumped in his jaw.
"You've always been susceptible to reasonable voices," Snape said.
Anger flashed hot, then turned cold. "I was told it was sensible."
He didn't blink.
"I was told it was safer," I said. "I was told.. " I stopped before the unsaid name could touch the air.
The castle groaned, low and deep, as if it recognised the shape of what I refused to speak.
Snape's voice dropped. "You were told."
Contempt. Not loud. Not dramatic. Enough to cut.
He stepped closer by one pace. The air between us tightened. My body responded before my mind could stop it. Pulse. Heat. A shallow breath corrected by force.
"You left," he said.
One fact. No embellishment. It hit harder than any accusation.
"I did," I said.
His eyes stayed on mine. Dark. Unforgiving. "And now you return."
"I don't expect anything," I said.
His gaze flicked once.. too fast to call it intentionalto my mouth, then back to my eyes. My chest tightened painfully.
The corridor under our feet vibrated.
A thin line of frost crawled along the seam where wall met floor, deliberate and wrong. It traced a rune I didn't recognise... new, sharp, designed to be seen.
Snape's wand was in his hand instantly.
"Move."
The rune pulsed. Frost melted into slick black sheen like ink in stone. The frost marked it.
The sheen activated it. The air tightened into a fist.
Snape caught my elbow and pulled me behind him. Brief contact. Efficient. It burned anyway, heat flaring under my skin.
The rune held his severing charm. Held it.
The stone split with a thin crack. A hairline fissure ran upward like bone breaking.
Hogwarts shuddered.
Pain speared behind my sternum. I gasped, hand to my chest. Snape's breathing changed, fraction deeper, harsher. He felt it too.
"This isn't random," I said, voice tight. "It's keyed."
"To us," Snape said.
The admission sat between us like a blade.
The fissure pulsed again. Lights flared sickly green, then dimmed. Cold poured out, spell-cold that made teeth ache.
I lifted my wand. "It's instructional," I said. "Someone's directing the castle's responses.
Snape's wand stayed aimed, posture rigid.
"Who."
"Ministry," I said. "Or someone who wants to look like it."
The fissure narrowed by a hair under our combined spells, not healed, just paused.
The corridor settled into a tense quiet. The air stayed too cold. The lights stayed wrong.
At the far end of the hall, a silhouette turned a corner, unhurried.
No proof. No face.
But the air tasted like Cassian Vale's calm.
Hogwarts breathed shallowly, strained.
And somewhere deep in the stone, something listened like it was being trained.
Someone wasn't waiting for the castle to break.
They were teaching it how.