The doleful sound. The Alma Perdita. "Cry of the Lost Soul." John, Uraso and Muro listening to the signals of the enemies. The night watch. Stalking. The answering cry. The Konotos. Sacrificial feasts. The dark of the moon. Its significance. The language of birds and animals. Their meaning. Discovery of cannibals. The telltale bone. Evidence of more than one tribe. Strange customs. Sacrifices of ancient times. Mexican rites. Superstitions. Previous history of the boys. Varney, Uraso and Muro. The Professor. The wreck and adventures. John's search for records, and inscriptions. Mysterious happenings. Waiting for morning. The plan outlined. The days of the sacrifices. Determine to prevent the killing of captives. Discovery of the natives in vicinity. Investigating the hills.