Some frequencies were never meant to be heard. When a massive psychic disturbance erupts beneath the Amazon, the Circle uncovers a lost city hiding the Emerald Conductor—an ancient machine capable of amplifying psychic power and draining the Earth itself. Now it has been activated. As reality destabilizes and traps awaken, the team must stop a force that is not only intelligent, but listening—before the signal spreads and the planet becomes part of the machine.