Another Culture novel, set in a universe where The Culture, a loose federation of various intelligent species across the galaxies, including humans and other biological beings, Drones and Ships (which have vastly greater intellect than humans). In this post-scarcity world, there is no money and no central authority.

However, an outside species of octopus-like beings are drawn into a war with the culture while a strange construct of vast power but no interaction except in its own defence appears out of nowhere. As usual, the power of the Culture stories are more about the social interactions between the various beings and the politics of the war, which hold up a mirror to our less ethical world.