The first sign was the hum.

A low, resonant vibration crawling through the floor of the safehouse like a slow wave before an earthquake. Gray’s eyes snapped open, his sensor rig flaring to life across his wrist.

“Something’s coming online,” he muttered. “Not residual static—this is live. It’s the Echo.”

Hale was already moving, grabbing his rifle and crossing to the shattered console near the east wall. The monitors that had been dead for days flickered on one by one—each ...