Sinbad and his crew intercept a homunculus carrying a golden tablet. Koura, the creator of the homunculus and practitioner of evil magic, wants the tablet back and pursues Sinbad. Meanwhile Sinbad meets the Vizier who has another part of the interlocking golden map, and they mount a quest across the seas to solve the riddle of the map, accompanied by a slave girl with a mysterious tattoo of an eye on her palm. They encounter strange beasts, tempests, and the dark interference of Koura along the way.

Sinbad must deliver a prince transformed into a monkey to the lands of the Ademaspai to restore him to his human form in time for his coronation. On the way he must contend with the evil witch Zenobia, her son and their magic, and several nasty-looking Ray Harryhausen beasties.