Mahit is deputed as ambassador from the tiny Lsel Station to the mighty Teixcalaanli Empire when her predecessor, Yskandr, dies in mysterious circumstances. More curious still is the fact that Lsel Station possesses a secret and unique technology: the imago machine. Imago is essentially a bio-chip that carries the endocrine memory of a person, and can be embedded and integrated into the brain of another person. (Phew, hope I got the description right!)
The trouble just keeps on piling up from there. Mahit finds that Yskandr’s imago in her brain has been sabotaged! Also, it seems imago technology isn’t so hush-hush after all — and several people are fighting over it… And the city where Mahit has been posted is an AI hive-mind which is malfunctioning… Oh, and there are new monstrous aliens at the gate…