The dome’s spacious interior is cool and dank. A rectangular corridor leads straight into the depths of the dome, while equally geometric — though perfectly curved — hallways run from each side of the main room. The whole thing appears to be carved of flat, grey stone, with a pebbly texture to its worked surfaces. Our friends’ boots clank against the stone floor, their armour creaking in the vast, open spaces. From the shadows above, they hear a group of unseen animals, tittering.