After three days of flight, my jail cell dipped towards the inner surface of what appeared to be an abandoned city. A ten-kilometre-tall ziggurat stood at the centre. Against any other backdrop, it would have appeared huge. Here, it barely registered as a blip on the darkened landscape. Fashioned from the same material as the rest of the structure, it appeared to be a node of some kind. A starburst of tubes and conduits radiated from its base in all directions, forming the web-like skeleton of the surrounding city. Points of light speckled the ziggurat’s slab-like sides and, as we drew closer, I saw these lights to be doorways identical to the one from which I had embarked. What first appeared to my tired eyes to be flickers on my vision resolved into a midge-like cloud of flying rooms, each following its own trajectory, and all of them coming and going from the doorways in the ziggurat like buses coming and going from a central bus terminal. Their activity gave the building the appearance of a beehive and I began to feel truly apprehensive. Until now, I had been more concerned about the humans following me, and had assumed the internal structure of the Brain to be as stark and derelict as its surface. But if the flying boxes I was seeing turned out to be more than simply forsaken relics acting out automatic routines, if they were in use, then maybe I was about to meet the inhabitants of this strange and barely comprehensible artefact.

The thought chilled my blood.

Fists squeezed into tight balls, I watched as my floating prison approached the towering side of the stepped pyramid.

How had all this gone unnoticed? Numerous alien races had scanned the Objects in the Gallery. None had reported so much as an opening on the surface, let alone this subterranean netherworld. Could it be this entire bubble existed outside normal space and time? It was certainly too gigantic to have been accommodated within the confines of the Brain, which was itself no larger than a moderately sized planet. Perhaps I had unwittingly passed through some sort of dimensional portal, into a kind of higher space—maybe even into the hypervoid itself? That would certainly go a long way towards explaining how the existence of a tiny star within a planet had gone unnoticed for so many hundreds of years.

And yet, that being the case, how had I found my way in here so easily?