The planet Mars has been inhabited by humans, but instead of children, the residents now rely on robotic servants, nicknamed "dolls". Layla is a highly competent fighter and adventurer with a heartbreaking history, and she explores different regions of the planet alongside two companions. Nei is a peculiar and exceptional doll who seemingly has some form of connection to Layla, while Speedy's expertise lies in breeding dolls. Layla, Nei, and Speedy are considered a menace to the rulers of Mars, who regularly launch attacks against them. With each assault, details of Layla and Nei's enigmatic past and destiny gradually come to light.