The breakthrough came from Valentine. While Sage stared at the screaming Core, she buried herself in the ancient architectural schematics of the Spire's foundation.
"Here," she said, her voice tight with discovery.
She overlaid two images. One was the current engineering plan of the Core and its support structures. The other was a scan of the pre-Desiccation geological survey.
"They didn't just build the Core on the source," she said. "They built it into a natural formation. See this?" She pointed to a ring of porous, resonant stone in the old survey. "The Aquifers' texts called it 'The Listening Chamber.' It's a natural amplifier. The Syndicate used it as the housing for their constriction bands."
Sage saw it. "So the Core isn't just forcing a scream. It's using the world's own natural ability to sing, and forcing it to scream instead. They perverted the amplifier."
Valentine nodded. "And look at the shape of the Chamber." She pulled up the scan of the fountain's spiral groove—the Vivification Sigil. With a few digital strokes, she scaled it up, rotated it.
It fit perfectly over the ring of resonant stone.
"The Stillpoint Spin isn't a small sigil you carve," Sage whispered, awe and dread rising in him. "It's the original shape of the place. The Chamber itself is the First Note. They didn't plug it with a dagger. They… they bent the note."
The puzzle's final piece clicked. Healing wasn't about removing the Core. It was about changing the vibration within the Chamber. They had to retune the amplifier.
It was a task of impossible, delicate scale. And they were standing right next to it.