In a future where Earth's population strain leads to interplanetary colonization, the ship 'Mesopotamia' suffers a fatal malfunction, leaving only 6 male survivors to establish a new society on the Earth-like planet 'Terra II'. Facing the absence of women, they resort to cloning and genetic manipulation, complementing their community with lifelike female androids known as 'Marionettes'. These emotionless machines serve their creators dutifully until a chance encounter with Otaru, an ordinary boy who awakens 3 unique Marionettes imbued with emotions through the enigmatic 'Maiden Circuit'. As Otaru guides them in understanding and embracing their feelings, a looming threat of world domination forces him and his 'human' Marionettes to defend their nation against peril.