Merciless sorcerer El Kerim (Pedro Armendáriz) uses black magic and mind control to wrest power from the king. His next move is to steal Princess Jana (Heidi Brühl), girlfriend to Capt. Sindbad (Guy Williams). To stop El Kerim, Sindbad and his men must find and destroy a mythical tower that protects the sorcerer's heart. Along the way, Sindbad faces constant danger: a barrage of scimitar-wielding warriors, monstrous birds, a many-headed, fire-breathing dragon and even a massive, menacing fist.