Earth has turned into a desert in the distant future. Sam, a sand pirate boy who lives in a sea of sand, searches for a mysterious gigantic moving object "OZMA", to avenge his brother. One day, Sam encounters a sand yacht being chased by Theseus, army of Cloned Human IC(Ideal Children). Sam saves a girl who gets thrown off the yacht as it overturns when a gigantic object suddenly appears with a blast of sand. In bringing her back to the Sand Pirate ship, Bardanos, she reveals her name as Maya.