A civilisazion has left a long long time ago it’s main planet.
A few thousands years later they send a probe to reactivate the main robot manager of the dormant city system, but things are not what they used to be, some things have evolved….
In SU the main civilization used to live in a giant volcano, their technology and language is music. Everything is coherant and is defined by it’s own ecosystem.
Source: The Game Website.