Watch on HDtoday. After extreme global warming hit earth, Humans made every effort to stay alive in underground compounds.They joined forces as the UHC (United Human Compounds) and maintained connection through the Mainframe (internet).Our heroine is a young girl, the only survivor of her community, living underground. After her father is killed by vandals, she is forced to go 'topside' (above ground) to find others in order to survive.