One hundred years ago, in the Purple Hills of Luesonia, seven gems were stolen from the crown of a crystal statue of the goddess Istarra. Each gemstone born on Luesonia was alive and could hold within their crystal hearts great magical power. If used together for good, great things could happen. If the gems were used for evil, Luesonia would become a dark world. Many years later, Kajis, an evil warlord, found one of the seven gems, the green gem, Shagara. As soon as he possessed Shagara, he desired the other six gems for their magical powers. Kajis sent two Bduds to kidnap the Spectra Clan from the Purple Hills and enslave them in his castle dungeon. From the members of the clan, he chose twins, ten-year-olds Danu and Cronus, for their unique gifts of magic to locate and retrieve the other six gemstones. If the twins chose not to go on the quest, Kajis threatened to kill all the members of their clan. Danu and Cronus experience exciting adventures on the gem quest. Along the way, they meet up with several willing accomplices, human and alien, to help them gather the remaining gemstones before the day of the full moons. Danu and Cronus and their new friends know they cannot allow Kajis to possess the gems of Istarra.