The challenge crystallized their purpose. They weren't just cleaning a basin; they were crafting a rebuttal.
Sage studied the moss. His scanner showed it was producing its own faint, simple harmonic—a biological resonance. "It's not just growing," he realized. "It's singing back. A very simple note. A note of… life."
He had a wild idea. "We've been singing at the poison. What if we sing to the life? We amplify the moss's own song. Use it as the foundational note for the next harmonic."
It was a leap from alchemy to biomancy. Lysander was cautious. "We risk accelerating it unnaturally. Creating a monster."
"Or we encourage it to do what it naturally wants to do: spread, heal, build soil," Sage argued. "We're not forcing. We're… lending it our choir."
They tried it. The Choir stopped their targeted pollutant notes. They listened, their sensitive resonators picking up the moss's faint biological hum. Then, gently, they began to amplify it. To harmonize with it.
The effect was not instant. But over hours, the patch of moss thickened. Its green deepened. It began to spread, not in a chaotic bloom, but in a slow, steady wave, following the harmonic pathways they provided. As it spread, its own song strengthened, creating a virtuous cycle.
They were no longer just cleaners. They were cultivators. They were using the Song not to impose an order, but to midwife an ecosystem.
The broadcast showed this too. The contrast was now stark: Charlotte's sterile, silent acre of artificial purity, versus a slowly greening, softly singing field of reborn life, messy and complex and alive.
The choice was no longer between control and chaos. It was between a silent, finished room, and a noisy, growing garden. The world, tuning in, held its breath. The demonstration was reaching its crescendo.