Refugees arrive in the Polity from eight hundred years in Agent Cormac's future. And once they are through, the gate they use is dumped into the sun, as something dangerous and non-human is in pursuit.
Cormac soon learns that the Maker civilization they have come from has been destroyed - by alien Jain technology. Orlandine, an augmented human, is studying this lethal tech in Cormac's timeline. She may manage to harness its power, or it might destroy her.
Meanwhile, Cormac is desperate to stamp down on this same technology, but someone or something is spreading it. And just outside humanity's Polity worlds, something very nasty indeed might just be pulling their strings