DEEP FOUNDATION

Three years after the four-city crisis, the task force has settled into something like routine — until a resonance anomaly beneath the stabilized Hub reveals a depth that shouldn't exist. Hydrogeologist Farah Haddad asks the one question no one thought to ask about a two-thousand-year-old stone network: where does the water go?

The answer leads Reza Sarwono's team into a water-distribution gallery, a thermal regulation corridor, and finally a single, breathtaking realization — the Hidden Layer was never the discovery. It was the surface of something considerably older, larger, and more deliberately engineered, and it has been quietly regulating the ground beneath an entire city for two millennia.