Spirit, or, The princess of Bois Dormant - Gwyneth Jones

Bibi (it means princess) is the sole survivor of a massacre. Lady Nef, the General's wife, stops the General taking her as a concubine, winning Bibi's eternal and passionate devotion. Years later, a diplomatic mission to a supposedly friendly planet ends in disaster. Bibi, now a junior officer in Lady Nef's household, is incarcerated with her mistress in the notorious high-security prison on Fenmu. Lady Nef, 150 years old when arrested, dies in prison; she bequeaths to Bibi her rank, her level of access to the AI systems that permeate the Diaspora of inhabited planets, and a highly secret set of 4-space co-ordinates. Bibi uses Lady Nef's death to escape from Fenmu, finds Spirit, an instantaneous-transit space pod, and follows Lady Nef's co-ordinates to a treasure beyond price: a virgin, perfect, uninhabited planet.

Soon after this, the mysterious, fantastically wealthy Princess of Bois Dormant makes her debut in the high society of Speranza, the Diaspora's capital city. Thus disguised, Bibi sets out to discover why she and her mistress were condemned to a living hell; and to punish the guilty. Twenty years have passed: Lady Nef's enemies now rule Speranza. As she uncovers a forgotten, ruthless and far-reaching conspiracy, Bibi's vengeance is transformed into a project of world-changing reparation.