The center stone was cold beneath Nico's palm in a way that had nothing to do with temperature. It was the cold of deep earth, of places the sun had never touched, of something that had been waiting in the dark long before the castle above had been raised stone by stone. The growl hummed through his bones, through the meat of his palm, through the roots of his teeth, and the wolf in him leaned into it like a hand reaching for a familiar warmth.
"You're doing that thing again," Sera said.
He didn't look at her. "What thing."
"The thing where you look at something ancient and terrifying and your eyes go all soft and hungry." Her voice was pitched low, but the tremor underneath it was real. "It's not a good look on you."
The scratches echoed from the corners of the chamber—faint, rhythmic, like something idly dragging claws across stone. Nico's fingers spread wider against the rock, pressing flat, feeling for the source of the vibration. It was there, beneath the surface, a pulse that didn't quite match his heartbeat but wanted to.
"You heard this before," he said. "In the tunnels under the west wing."
Sera shifted her weight, her wand still raised, the tip tracing a slow circle in the air as if testing the currents. "Heard something. Thought it was the pipes, or rats, or my own head getting too clever for its own good." A pause. "It wasn't any of those."
"No."
"It knew your name, Nico."
He didn't answer that. Couldn't. The wolf in him had gone very still, ears pricked, hackles half-raised, staring at the dark between the stones like it could see through to whatever lay beneath. And something in that dark was staring back.
The growl swelled, a low, grinding sound that Nico felt in his sternum, in the hinge of his jaw, in the soft place behind his eyes. The stone under his palm was vibrating now, a fine, insistent tremor like a plucked string that wouldn't stop ringing. Sera's breath misted in front of her face, and she took a step closer to him, close enough that he could smell the ink on her fingers and the faint herbal sharpness of whatever potion she'd been brewing before all of this.
"It's not going to stop," she said. "Whatever it's doing, it's not going to stop until—"
The crack split the rock with a sound like a snapped twig.
It was small at first, a hairline fracture running from beneath Nico's index finger down toward the edge of the stone, no wider than a thread. But it was there. It was real. And the growl beneath it changed pitch, rising into something that might have been anticipation.
Sera's wand came up higher. "Nico."
"I didn't do that."
"I know you didn't do that. That's the problem."
The crack widened, a slow, deliberate creep of stone splitting against itself, and a breath of cold air rose from the dark beneath. It wasn't the chill of the chamber, which was already cold enough to ache in the joints. This was older. Deeper. It smelled of iron and dust and something else—something animal, something that had been sealed away so long it had forgotten what the sky looked like.
Nico's hand stayed where it was.
He felt the wolf in him press forward, not in panic but in recognition, the way a hound might lean toward a scent it had been tracking for days. The cold air curled around his wrist, his forearm, his shoulder, and it was like being touched by something vast and patient and terribly, terribly old.
"It knows you," Sera whispered. "It's not trying to get out—it's trying to get you to let it out."
The crack widened again, another inch, and the growl resolved into something almost like a word. Not quite. A shape of sound that might have been a name if the throat making it had been human. Nico's fingers curled against the stone, and he felt the vibration run up his arm and settle in his chest, in the hollow where his heartbeat lived.
His heartbeat, which was not entirely his own anymore.
Cleo.
The thought came unbidden, and with it, a distant pulse—warm, steady, alive. She was still in Vane's office. Still negotiating. Still breathing, and he could feel it, the faint echo of her heart beating in time with his own, the blood oath humming between them like a second thread pulled taut.
The cold air pulled at his chest, and for a moment, the growl beneath the stones sounded almost like a question.
"Nico." Sera's voice was tight now, the tremor gone, replaced by something harder. "Step back."
"It's been waiting for me."
"I don't care if it's been waiting for you since before your great-grandmother was a twinkle in someone's eye. Step back."
He didn't move. The wolf in him had gone quiet, watchful, and the quiet was worse than the growling. It was the stillness of a predator that had found its prey and was deciding whether to move.
The scratches in the corners had stopped.
That was what finally broke through—the silence where the scratching had been. Nico's eyes lifted from the stone, scanning the edges of the chamber, the shadows between the torch sconces, the places where the darkness pooled thick enough to hide things. Nothing moved. Nothing breathed. But the absence of the sound was louder than the sound itself had been.
"I don't like this," Sera said.
"You've said that."
"I'm saying it again because you're not listening."
The crack in the stone had stopped widening, but the cold air was still rising, curling around Nico's legs like a tide. He could feel it against his skin, through his boots, through the wool of his trousers, and it carried with it a weight that pressed against his chest, his lungs, the space behind his ribs where the wolf lived.
Something hummed.
It wasn't the growl. It was a different sound, higher, thinner, like a wire drawn tight and struck. Sera's wand flickered, and she made a sound low in her throat, half surprise, half fear.
"What?" Nico's voice came out rougher than he'd intended.
"The stone." Her eyes were fixed on the circle beneath them, on the cracks that now spiderwebbed across the center stone. "It's pulsing."
He looked down. She was right. The stone wasn't just vibrating anymore—it was moving, a slow, rhythmic swell and fall like a chest breathing. Like a heart beating. Like something alive under the earth, stirring after a long, long sleep.
And the rhythm of it matched his heartbeat.
Nico felt the wolf surge, not with fear but with something closer to longing, a pull so strong it made his knees lock and his muscles tense with the effort of not stepping forward. The cold air wrapped around him, and for a moment, he could almost see it—a shape in the dark beneath the stones, vast and patient, waiting with the kind of stillness that only came from centuries.
"It's not going to hurt me," he said, and he wasn't sure if he was telling her or himself.
"You don't know that."
"I know it's been waiting."
"Waiting doesn't mean friendly, Nico. It means patient."
He wanted to argue. The wolf in him wanted to argue, wanted to press closer, wanted to lay his palm flat against the cracked stone and let whatever was beneath it rise up and meet him. But Sera's hand closed around his arm, her fingers digging in hard enough to bruise, and the contact snapped something in his chest.
"Nico, don't."
The words landed into silence.
The crack was still there, still widening, a thin, dark line splitting the center stone like a wound that refused to close. The cold air was still rising, curling around his ankles, his wrists, his throat, and the hum was still there, a wire drawn tight, waiting to be struck again.
And beneath it all, the growl had gone quiet.
Not gone. Quiet. Waiting.
Nico's hand stayed where it was, flat against the cold stone, and he could feel it—the pulse of the thing beneath, slow and patient, matching his heartbeat beat for beat. The wolf in him leaned closer, and the dark beneath the stones leaned closer too.
Sera's grip tightened on his arm, her fingers digging in hard enough to hurt, and her breath was warm against his shoulder, a small, living warmth in all that cold.
"Please," she said, and the word cracked.
The crack in the stone widened another inch.
The cold air rose.
It rose like a tide, but not the tide of the sea—the tide of something that had been held back for so long it had forgotten how to be anything but pressure. It wrapped around Nico's ankles, his calves, his knees, and with it came a sound that was not quite a growl and not quite a word, a sound that vibrated in the hollow of his chest and made his teeth ache in their sockets.
Sera's grip on his arm was the only anchor he had. Her fingers were white-knuckled, digging into the muscle of his forearm hard enough to leave bruises, and her breath came in short, sharp bursts against his shoulder blade.
"Nico." Her voice was barely a whisper now, scraped raw. "Nico, please. Whatever this is—whatever it wants—it's not worth—"
"You don't know what it wants."
"Neither do you."
The crack in the stone was wider now, a dark fissure running the length of the center stone, and from it came a light that was not light at all—a faint, sickly luminescence, like the glow of rotting wood, like something that had been buried so deep it had learned to make its own illumination. It pulsed. Once. Twice. In time with the heartbeat that was not entirely his own.
Cleo.
The thought came again, sharper this time, and with it a sensation that was almost physical—a warmth in his chest, a pressure behind his ribs, as if someone had pressed a hand to his sternum from the inside. Through the oath, through the blood that bound them, he could feel her. Not her thoughts, not her words, but her presence, a steady pulse of aliveness that cut through the cold like a blade drawn across a whetstone.
She was still in Vane's office. Still breathing. Still waiting for him to come back.
The cold air pulled at his chest, and the growl beneath the stones rose again, a low, grinding sound that seemed to shape itself around a single syllable. His name. Not quite. A shape of sound that might have been his name if the throat making it had been anything like human.
"It's calling you," Sera said, and there was something in her voice he'd never heard before—not fear, not anger, but something closer to grief. "It's been calling you for a long time, hasn't it? Before tonight. Before the oath. Before any of this."
He didn't answer. Couldn't. Because she was right, and the knowing of it settled in his chest like a stone dropped into deep water.
He'd felt it for weeks. The pull. The restlessness. The way his skin prickled when he walked over certain flagstones in the castle corridors, the way his dreams had turned dark and deep and full of the sound of breathing that wasn't his own. He'd told himself it was the moon, the pack, the familiar ache of a wolf who hadn't run in too long. But it wasn't any of those. It was this. This chamber. This stone. This thing that had been waiting for him since before he was born, patient as a buried root.
The scratches in the corners had started again, but they were different now—closer, sharper, a sound like claws dragged across stone in a pattern that was almost deliberate. Almost like a message. Sera's wand swung toward the sound, her jaw tight, and the tip of the wand flickered with a light that was barely there, a candle flame in a room full of shadows.
"There's something in the walls," she said.
"I know."
"No, I mean—" She cut herself off, her eyes scanning the edges of the chamber, the places where the torchlight faltered and the darkness pooled thick enough to hide things. "It's not just the thing under the stone. There's something else. Something that's been watching us since we came down here."
Nico's hand stayed flat against the cracked stone, but his eyes lifted, scanning the same shadows she was searching. He could feel it now that she'd named it—a presence at the edges of his awareness, a weight in the dark that didn't quite belong to the chamber's chill. Something old. Something patient. Something that had been here long before the stones had been laid, and would be here long after they crumbled to dust.
"Don't move," he said.
"Wasn't planning to."
The growl beneath the stones had gone quiet again, but the hum was still there, a wire drawn tight and trembling, and the crack in the center stone was still widening, a slow, deliberate creep of rock splitting against itself. The cold air rose around them, thicker now, pressing against Nico's chest like a weight, and through the oath he felt Cleo's heartbeat quicken—not with fear, but with something else. Something that felt almost like recognition.
She could feel it too.
The thought landed in his chest with the force of a physical blow. Through the blood oath, through the bond that tied them, she could feel the cold, the pull, the thing beneath the stones reaching for him. And she wasn't afraid. She was curious. She was leaning into it, the way she leaned into every mystery, every secret, every dark corner of the world that promised answers if she only dared to look.
"Nico." Sera's voice was tight, controlled, the voice of someone who was one breath away from panic and refusing to show it. "Whatever you're feeling right now—whatever she's feeling—you need to push it down. Focus on the room. Focus on the stone. Focus on what's actually in front of you."
"I am focused."
"You're not. You're thinking about her."
He didn't deny it. Couldn't. The truth of it was written in the way his hand stayed flat against the stone, in the way his fingers curled against the rock as if he could feel her pulse through it, in the way the cold air seemed to wrap around him like a second skin, pulling him toward the dark.
The scratches in the corners stopped again.
The silence that followed was worse than the sound had been. It was the silence of something holding its breath, the silence of a predator that had gone still and was waiting for its prey to make the first move. Nico felt the wolf in him crouch, felt his own muscles coil with the instinct to run, to fight, to do anything but stand here with his palm flat against a stone that was breathing.
"It's not going to hurt me," he said again, and this time he wasn't sure if he was telling her or himself. "It's been waiting too long for that."
"Waiting doesn't mean friendly, Nico. It means patient."
"I know what it means."
"Then why are you still standing there?"
He didn't have an answer for that. Or rather, he had too many answers, and none of them were the kind you could say out loud. Because the wolf in him wanted to stay. Because the thing beneath the stones felt like home in a way the pack never had. Because for the first time in weeks, the restlessness that had been gnawing at his bones had gone quiet, replaced by something that felt almost like peace.
The crack in the stone widened another inch.
The cold air rose, curling around his wrists, his throat, his jaw, and with it came a sound that was almost a word. Not quite. A shape of sound that might have been a name if the throat making it had been human. And beneath it, the hum, the wire drawn tight, waiting to be struck again.
Sera's grip on his arm tightened, her fingers digging in hard enough to hurt, and her breath was warm against his shoulder, a small, living warmth in all that cold.
"Nico, don't."
The words landed into silence.