Late in the century, due to the overpopulation on Earth, efforts at off-world colonization are made. Planet Terra II is one of these new colonies, with an all-male society, where the only females are high-performance androids without emotions, called Marionettes. The Marionettes are used for combat, to perform menial labour, and as a replacement for the female population.
In the city-state of Romana, which resembles medieval Italy, the Saber Marionettes Cherry and Lime now accompany Junior, the heir to the country's throne, while Bloodberry serves his father — the current High Official. However, a criminal known as Star Face attempts to take the throne, using three marionettes of his own and threatening Junior's life. Cherry, Lime and Bloodberry must protect the boy and help Romana become peaceful once more.
