On the smallest of the gas giant's three major moons, an airless, cratered thing smaller than Earth's Moon, the Moonwalkers survey found pearly crystal shards 25 to 30 metres tall growing out of the surface. They turned out to be a sort of silicon-based bacteria colony, an alien analogue of soil bacteria, metabolising radiation from deep space along with silicate elements in the regolith, and joined by lattices of the same bacteria running through the ground between them.

The crystals are a single telepathic collective. It picked out the people with MES in the survey party, Simul, Walkr, Willow and Philo, and learnt the concept of trade from them, then offered a mineral-rich, stable lava-tube site for an outpost in return for leaving the crystals undisturbed and sharing knowledge of mutual threats. It may make contact again.