The silver mist swallowed them whole.
It clung to their clothes, cold and damp like a morning fog, but tasted faintly metallic on their tongues. As they walked, the floor beneath their boots changed from stone to something softer — a woven mesh of silver threads stretched taut over emptiness. Each step sent a shiver through it, like plucked harp strings.
Lyra whispered, "We're… walking on sound?"
Aric crouched, brushing his fingers against the threads. They vibrated faintly. "Condensed resonance," he murmured. 'Vault's woven its own floor out of echoes. One wrong move and it'll drop us straight into… whatever that is.' He glanced down. The mist parted briefly to reveal a chasm of swirling grey shadows below.
Lyra made a face. "Love what they've done with the place."
He smirked. "Very chic. Early death trap."
They walked on, their footsteps muted. The mist shifted ahead, parting to reveal a cavernous hall. It looked like the inside of a cathedral built by no human hand: high arches formed from interlaced chains, walls studded with closed eyes like pearls. At the center, suspended over the void, hung a giant heart of silver threads. It pulsed slowly, each beat sending tremors through the floor.
Lyra stopped dead. "That's…"
"The Vault's heart," Aric finished softly. "Third whisper."
The heart shuddered. Threads unraveled from it, stretching down like tendrils. As they touched the floor they solidified into shapes — four tall figures, vaguely human but built of braided silver strands. Their faces were masks of blank metal. Each held a different instrument: a bell without a clapper, a drum without a head, a flute with no holes, a harp of broken strings.
Lyra took a step back. "Guardians?"
Aric's jaw tightened. "Manifestations. Last two trials were about shaping and hearing. This one's about beating it."
"Beating what?"
He glanced at the heart. "Ourselves. Our rhythm. Our pulse."
The figures raised their instruments. No sound came out, but the silver threads underfoot vibrated violently. The mist trembled. A pulse slammed into Aric's chest like a fist, staggering him.
Lyra gasped. "What was—?"
He wiped blood from his nose. "Resonance attack. They're trying to sync our hearts to the Vault's."
"What happens if they succeed?"
"We stop being us."
"Oh good."
The four figures began to move, slow and deliberate. Each step sent ripples through the floor. Their blank masks tilted toward Aric and Lyra.
Aric flicked open the Mirror. Its black edge pulsed faintly. "We'll need to disrupt the rhythm. Break their beat."
Lyra's fingers twitched, threads of black forming automatically. "I can weave a counter-pattern."
"Do it. I'll distract them."
He darted left as the first figure swung its empty bell. The motion sent a wave of compressed air rolling across the floor. He dropped flat; the wave passed overhead, making the threads hum like a thousand bees.
He rolled to his feet, flung the Mirror forward. Its black surface caught the next pulse, bending it sideways. The wave struck the second figure instead. It staggered, silver strands unravelling at its shoulder.
Lyra knelt, eyes closed, hands moving rapidly. Black threads laced into the silver under her, twisting the pattern. She whispered to herself, 'Over, under, cross, knot… match the rhythm, invert it…'
The figures turned toward her. One raised its flute; though no sound came out, a spear of pressure lanced toward her. She gasped, threads faltering.
Aric slammed into the figure's side, Mirror up. The spear glanced off, shredding the edge of his coat instead of her. He snarled, swinging the Mirror upward. It cracked across the figure's mask. Silver strands flew like sparks.
Lyra didn't open her eyes. "Buy me another thirty seconds."
He grinned grimly. "Done."
The third figure advanced, harp raised like a blade. Aric ducked under its swing, kicked its knee. The silver strands there snapped, but immediately rewove. He cursed under his breath. "Persistent."
He flicked the Mirror again, catching a pulse from the drum. It rebounded into the harp-figure, staggering it back.
Lyra's threads thickened, weaving a dark lattice under them. Her lips moved soundlessly: 'Reverse, reverse, reverse…' The lattice pulsed once, out of sync with the heart above.
The silver heart shuddered. Its next beat stumbled, like a skipped note.
Aric saw it. "It's working!"
"Almost…" she hissed.
The bell-figure swung again, sending a wave at Aric. He planted the Mirror into the floor. The wave split around him, but the force drove him to one knee. His ribs ached. He spat blood. "Do it now, Lyra!"
She slammed her palms down. The black lattice under them surged, rising up like a net around the four figures. It wrapped their limbs, pulling tight. The figures struggled, their instruments shuddering. The silver heart above them beat wildly, off-tempo.
Aric staggered to his feet. "Need a finish!"
Lyra's eyes snapped open. "The heart! Hit it!"
He didn't hesitate. He sprinted across the vibrating floor, Mirror raised. The heart's threads reached down, trying to snag him. He ducked, rolled, came up on one knee at the platform's edge. The heart loomed overhead, pulsing frantically.
He leapt.
For an instant he hung in the mist, weightless. Then he drove the blackened Mirror into the heart's surface.
The silver threads screamed. A burst of light blinded him. The heart convulsed, throwing him backward. He crashed onto the floor, rolling. The Mirror clattered out of his grip.
Lyra cried out his name. The net around the figures dissolved. They froze, then slowly unraveled into drifting silver filaments. The heart above them beat once more, then steadied — slower now, calmer.
Aric groaned, pushing himself up. "Did… we…?"
The mist brightened. The woman's voice whispered all around them: "Third whisper learned. Beat your own rhythm, or be beaten."
A silver glow flowed down from the heart, washing over them. Lyra felt warmth spread through her chest, like a second heartbeat aligning with hers, then fading. Her black threads melted back into nothing.
She staggered to Aric, hauling him up. "You're insane."
He grinned weakly. "Strategist."
"Idiot strategist."
"Fair."
They stood together as the heart slowly withdrew into the ceiling, its tendrils curling back. The silver mist thinned, revealing a new path: a narrow bridge of woven light leading away from the chamber.
Lyra exhaled shakily. "Three whispers down."
Aric picked up the Mirror. Its black edge was gone, replaced with faint silver veins. He studied it. "Looks like the Vault's… imprinting."
"That's good?"
"Could be. Could also explode later. Fifty-fifty."
She laughed breathlessly. "Comforting."
They stepped onto the bridge. It swayed gently, but held. Beneath them the chasm of shadows receded, whispering faintly like a sea at low tide.
After a moment she said, softly, "What did you see, back there? When the whispers came?"
He glanced at her. "You first."
She bit her lip. "I saw… home. And all the things I never said. Things I wanted to tell my mother before…" She trailed off, shaking her head. "It's like the Vault pulled them out."
He nodded slowly. "It does that."
"What about you?"
He smiled thinly. "Another time."
She rolled her eyes. "Of course. Strategist."
He chuckled, but his eyes stayed on the shifting mist ahead. 'Third whisper. How many more before we reach the fragment? And how much of us will be left?'
The bridge curved upward into an archway carved with bells and eyes. A faint golden light shone beyond it. They reached the threshold, pausing. Behind them the Vault's heart pulsed once, a slow, final beat.
Lyra looked at him. "Ready?"
"No," he said honestly. "But let's go."
She smiled faintly. "Good answer."
Together they stepped through the archway.