Tarzan the Invincible — Edgar Rice Burroughs

La was in trouble. The high priestess of the Flaming God in the ancient city of Opar -- forgotten outpost of Atlantis -- had been betrayed by her people and locked in the eon-haunted dungeons until Tarzan came to rescue her. La still loved Tarzan, but Tarzan had brought her to his people, and then left her. Now, together with a strange woman of Tarzan's kind, she lay bound in the tent of an Arab slave-trader, dreading her certain fate. Meanwhile, Tarzan was beset by a strange band of men who had invaded his land...led by a madman bent on evil subversion!