Ain
Ain is the rural department near Lyon where Steven grew up. In the wiki, it represents the social narrowness of childhood in contrast with Lyon, Paris, and California.
Childhood setting
Steven was raised near Bourg-en-Bresse, in a rural environment. The record presents this setting as socially limited and poorly matched to him.
He was bullied, changed schools multiple times, and did not find peers who matched him. The later autism diagnosis gives this mismatch a different explanation, but the geographic contrast remains important.
Contrast with cities
Lyon was the first urban counterpoint. Paris later became the chosen city. California became the distant place where the absence of familiar structure forced a confrontation with the self.
Ain therefore functions as origin, not destination. It is the background from which the city arcs make sense.