The Astra Signal. Book 3 Echoes of the Lattice

When Jean and Claire return from the Seed, they expect the world to have changed. Instead, the ocean and sky look the same-until the Lattice begins to sing. A planetary network buried in rock and sea has awakened, calling out coordinates that could heal the planet-or hand its power to the highest bidder. Pursued by rival states, a ruthless consortium, and mercenaries who turn repair into ransom, the former engineer and the security specialist must do the impossible: prove that stewardship matters more than ownership.
With Isabel's hard-earned misdirections, Thorne's hungry science, and Penhaligon's legal theater, they stitch together a fragile plan-witnessed hands, hardened logs, and a new law born in light: the Vesper Protocol. Fast, human, and quietly terrifying, Echoes of the Lattice asks how much of yourself you will give to save the world, and whether two people's promise can hold a planet against those who would make it a ledger.
The Seed has asked for stewards. The world wants something else. Which will win?