In the depths of the Amazon rainforest, a group of explorers embark on a perilous quest to find their missing brother, only to stumble upon a sinister plot by a mad scientist who has created a fungus monster that feeds on the local inhabitants. The "Cave of the Dead" is home to foamy, fungus-covered monster men, and the expedition soon discovers that they are trapped in a desperate fight for survival against an unstoppable force of nature.