Mathematician Lakshmi Nayak receives a letter from her future self about faster-than-light travel. The equations work, and the letter itself seems to prove the possibility will someday be realized. But her paper on the topic is fiercely criticized, and she's warned away by a sinister Alliance agent. After defecting to the Union, she gets an unexpected offer: "I can build your ship." Shipbuilder John Grant learns of a secret project, which unknown to the world has been traveling to the stars for decades: Black Horizon.

Biologist Emma Hazeldene works for Black Horizon on an alien world, Apis, whose life has clearly come from Earth, investigating rock formations that are thought to be an alien, crystal-like intelligence. But refugees exiled to a hard life in the wilds of Apis already know more than the scientists have ever suspected. Everything changes when the rocks wake up, with dire results. As secrets emerge and rival powers seize advantage, three worlds are shaken to their foundations—and all involved have to fight for their lives, and their futures.

Science fiction legend Ken MacLeod begins a new space opera trilogy by imagining humankind on the precipice of discovery—the invention of faster-than-light travel unlocks a universe of new possibilities, and new dangers.