Severus had known, deep down, that it would come to this.
Lucius never gave without cost. Every lesson, every kiss, every intoxicating glance was an investment. And investments demanded return.
Still, when the moment arrived, Severus's chest clenched as though a noose had tightened around it.
The Slytherin common room was empty, shadows rippling across the green-lit stone. Lucius stood before the fire, his figure cut in silver and shadow, pale hair gleaming like a blade.
"I have a task for you," Lucius said without preamble.
Severus swallowed. "Anything."
Lucius's smile curved, elegant and merciless. "Good. Then listen closely. Potter and his lapdogs are planning another of their idiotic escapades. I want to know what it is."
Severus stiffened. "You want me to spy on them?"
"Not just spy," Lucius murmured, stepping closer. "I want proof. Words I can use. Leverage."
Severus's throat worked. "Why?"
"Because information is power," Lucius said softly, circling him like a predator. "And because I want to know if your loyalty belongs to me… or to the little omega who still thinks he can save you."
Severus's breath caught. Lillian.
The next day, the opportunity presented itself. Lillian found him in the library, sliding into the seat beside him with cautious warmth.
"Sev… I'm sorry about before," Lillian whispered. His voice trembled, but his smile was genuine. "James went too far. I tried to stop him."
Severus's chest tightened. For a moment, he wanted nothing more than to lean into that kindness, to confess everything, to be forgiven before he was damned.
Instead, he forced his voice steady. "What were you and Potter whispering about earlier?"
Lillian blinked. "What? Oh—nothing. Just… plans. We were thinking of sneaking out after curfew. Something stupid, really."
"Tell me," Severus pressed. His heart pounded. Lucius's voice hissed in memory: I want to know if your loyalty belongs to me.
Lillian frowned. "Since when do you care about James's nonsense?"
"Since it might get you hurt," Severus said, the lie tasting like ash. "Please, Lillian. I just… I need to know."
Lillian's eyes softened. He hesitated, then whispered, "Alright. But only because it's you. We're meeting by the Astronomy Tower. Midnight. James thinks it'll be funny to… well. You know him."
Severus nodded, stomach churning.
Lillian had trusted him.
And he was going to betray that trust.
That night, Severus carried the secret to Lucius like an offering.
"They'll be at the Astronomy Tower," Severus whispered, hating the shake in his voice. "Midnight."
Lucius's smile was slow, triumphant. "You've done well."
Severus's chest twisted. "What will you do with it?"
"Nothing too terrible," Lucius said lightly, though his eyes gleamed with cruelty. "Just enough to remind Potter who truly holds sway."
Severus's stomach lurched. "If Lillian—"
"Your precious Lillian will be fine," Lucius purred, drawing closer. "I would never damage what you cherish. That would ruin you, and you're far too entertaining when you're whole."
He kissed Severus then, fierce and claiming, and Severus let him, desperate to drown the guilt clawing inside him.
But when midnight came, and the Astronomy Tower echoed with shouts—Potter roaring, Lillian crying out, curses flying—Severus could not escape the truth.
His betrayal had teeth.
And it had sunk deep.
The next morning, Lillian sought him out, face pale, voice trembling.
"Sev… someone told Lucius where we'd be. He ambushed us. James is furious. And I—" He broke off, eyes wet. "I thought I could trust you."
Severus's mouth opened, but no words came. His throat was raw, his chest hollow.
Lillian's voice cracked. "Tell me it wasn't you. Please."
Severus couldn't.
The silence stretched, damning.
Lillian's breath shuddered. His eyes hardened through the tears. "Then I don't know who you are anymore."
He turned and walked away.
Severus stood frozen, every part of him screaming to call out, to take it back, to beg for forgiveness.
But behind his ribs, the chain tightened, and he heard Lucius's voice again: Chains aren't always shackles. Sometimes they are the only thing that hold you together.
And Severus clung to it, even as the last piece of Lillian's trust shattered into ash.