Eclipse phase (think before asking)
A smallish torus habitat, recently refurbished into an ecumenic monastic hab where visitors can live in ascetic quiet. They are expected to help maintain the habitat, but beyond that people keep to themselves in small cells. The Zhang (a gnostic-daoist cult) are very unwilling to inquire into who come and go or what they think as long as they follow the habitat rules. Some outsiders joke that the Retreat is a spiritual morph storage unit.