Four billion years ago, something was left behind to keep the Earth alive - and it is running out of time to tell someone before it dies.
Dr. Carrie Matthews reads the ground for a living. On the flank of a Cascade volcano, three months after the mentor who made her a geologist went down in a small plane, she finds a signal in her seismic data that has no business existing - a pulse buried deep beneath the Andes, keeping time to four decimal places. Natural things wander. Made things keep time. She labels the screenshot probably nothing and cannot stop thinking about it.
It is not nothing. Recruited to a secret camp on the Chilean altiplano - a fake construction site over a set of impossibly smooth tunnels - Carrie learns what the pulse is: a machine older than the oxygen in her lungs, built to hold Earth's magnetic field together so that life could begin. It has been alone since its makers vanished. It has been trying to reach the surface for eight hundred and forty-seven years. And it is dying - the rock it lives in is sinking into the mantle, and when it fails, the sky that shields every living thing fails with it.
To save it, a handful of strangers have a few months to build a mind a new home and carry it across the gap while it can still guide them. But the longer Carrie listens, the more the thing underground becomes a someone - precise, curious, learning grunge through the bedrock, mourning creatures no one else remembers. When it asks for a name, it chooses the one she is still grieving. And when she understands what its slow death has already cost her, the work stops being a rescue and becomes something closer to a reckoning.
Some signals you spend a whole life learning to hear. Some you answer with everything you have left.
Perfect for readers who love:
First contact where the intelligence is older, stranger, and closer to home than the starsAn unlikely, unforgettable friendship between a human and a nonhuman mindWarm, humane, idea-driven science fiction that trades action for wonderGrief, memory, and healing rendered with the precision of real scienceA small, brilliant found-family team against an impossible deadlineSaving Roger is a standalone novel.