The Gzilt civilisation is preparing to Sublime - to leave the material universe and ascend to a higher dimensional existence. In their final days in the Real, a secret about the Gzilt's founding threatens to surface, and powerful factions on all sides would prefer it stayed buried. When the Regimental High Command is destroyed, Lieutenant Commander Vyr Cossont - a musician trying to master a piece written for a four-armed player - is drawn into a desperate search for a man who has lived for nearly ten thousand years and may hold the key to the truth. The final Culture novel, a story about endings - of civilisations, of secrets, and of Iain M. Banks' extraordinary series.