Shipwrecked while escorting the Princess of Serendip to her bridegroom, Sinbad discovers that she has been abducted by the wicked magician, Abdul Alhazred, who plans to sacrifice her in an attempt to open a dimensional gate and summon the Great Old Ones-demonic gods from beyond the stars. Accompanied by a motley crew of alchemists and slave girls, princes and policemen, Sinbad sets out to foil the evil sorcerer's plot. The journey will take them from lost desert cities to mysterious jungle islands, from the streets of Samarkand to the fabled Plateau of Leng, until at last Sinbad alone stands between the peoples of the Earth and slavery to the forces of cosmic evil...