Michael Poole finds himself in a very strange landscpe...
This is the centre of the galaxy. And in a history without war with the humans, the Xeelee have had time to build an immense structure. The Xeelee Belt has a radius ten thousand times Earth's orbital distance. It is a light year in circumference. If it was at rest it would have a surface area equivalent to about thirty billion Earths.
But it is not at rest. It rotates at near lightspeed. And because of relativistic effects, distances are compressed for inhabitants of the Belt, and time drastically slowed.