The tunnel bent downward until the ceiling pressed close enough to brush their heads. The water was black now, colder, full of silt. Every breath tasted of iron and brine. Faint echoes of the Depthborn's hiss still clung to Aric's skull, fading like a nightmare at dawn.
He kept his pace steady, forcing his heartbeat down. Lyra's threads glowed faint blue around her fingers, casting a dim light. Her cloak clung wetly to her shoulders, dripping with each step.
"You're pale," she murmured, glancing at him. "How long were you inside their pattern?"
"Seconds," he said. "Felt like hours."
"You're lucky you came back at all."
Aric didn't answer. The Mirror pulsed against his ribs like a heartbeat, its surface whispering faintly. Memory ghosts flickered at the edge of his thoughts: a rush of black water, teeth, hunger. He shoved them aside. Not now.
The tunnel widened abruptly. They stepped out onto a ledge overlooking a cavern vast enough to swallow a city block. Stalactites of pale crystal hung from the ceiling like frozen lightning. The water below reflected them, turning the whole space into a fractured mirror of light. The air was cold, still, and heavy with a scent like scorched salt.
Lyra's breath caught. "By the threads… no one's mapped this."
Aric crouched, scanning the cavern. Half-submerged ruins jutted from the water—arches of corroded metal, shattered walkways, what looked like a collapsed elevator shaft vanishing into black depth. An ancient maintenance sign hung crookedly from one pillar, letters faded: ZONE 0 – ENTRY FORBIDDEN.
"They built over something old," Aric murmured. "Older than the Reach itself."
Lyra knelt at the edge, trailing her fingers in the water. "This much raw Echo… it's bleeding up from the trench."
Her threads flicked outward like antennae. A frown tightened her mouth. "There's something down there. Big."
Aric followed her gaze. Beneath the surface, faint glimmers of movement swirled—currents twisting into patterns, like script written in water. He couldn't read it, but it made his teeth ache.
"Guild patrol's not coming this far," Lyra whispered. "They'd never risk it."
"Exactly," Aric said. "Which makes it the perfect place to hide."
Lyra looked at him sharply. "Hide? You want to study that fragment here?"
"I want to understand it," he said. "If the Sanctum or the Guild get it, they'll lock it away or tear me apart for it. Down here, at least, I get a chance."
She stared at him for a long moment, then sighed and shook her head. "You're insane."
"Maybe," he said. "But so is the world."
He set the satchel on the ledge and pulled out a compact field lantern, clicking it on. Warm light spilled across the crystal walls, turning them gold. For a moment the cavern looked almost beautiful, like a cathedral drowned in light.
Then the water below stirred.
A ripple spread outward, slow and deliberate. Something vast moved beneath the surface. The glimmers of pattern brightened, twisting tighter. A low sound rolled up from the depths—not a hiss, but a chord, deep enough to vibrate their bones. The lantern's flame guttered.
Lyra's threads snapped back to her fingers. "That's not Depthborn," she whispered. "That's a Chord-Beast."
Aric's stomach went cold. He'd heard the stories—constructs born of Resonance gone wild, half-sentient, able to sing a path into an unwary mind. No one had seen one in decades; they were supposed to be myths, like the first Pathfinders.
The chord deepened. Water climbed the cavern walls in small, trembling waves.
Lyra's eyes flicked to Aric. "We have to move. Now."
"Too late," he said.
The water split.
Something rose—a shape like a serpentine spine made of light and iron, scales flickering with the glow of dozens of stolen chords. Its "head" was a crown of crystal shards, its "eyes" two pits of silver fire. The air vibrated with its song, a low, thrumming tone that made Aric's teeth chatter. In its presence the Mirror in his satchel pulsed violently, as if trying to answer.
Lyra grabbed his arm. "Aric—"
"I feel it," he said hoarsely. The Mirror was resonating with the beast's song, trying to lock into its pattern. If he let it, he might glimpse its nature, even borrow a fraction of its power. But the cost…
The beast's song swelled, waves slapping against the ledge. Crystal shards rained from the ceiling. Lyra's threads flared blue as she tried to weave a barrier. "Choose," she hissed. "Fight or run."
Aric's hand hovered over the satchel. The Mirror's whisper filled his head, half-words of something older than the Reach.
He exhaled slowly.
"Neither," he said. "We listen."
Lyra's eyes widened. "What—"
But Aric was already pulling the Mirror free, its surface blazing silver in the dim. He held it up toward the beast like an offering.
The chord deepened again, rolling over them like a tide.