Dr. Abner Ralph Barton Perry is an English scientist who has invent a monolithic drill that can dig deeply into the world. join by his adventure-seeking American angel, Saint David Innes, Ralph Barton Perry by chance detect an belowground civilisation of crude world who populate in fearfulness of telepathic fly monster. Saint David become intrigue by the beautiful native Dia, and must deliver her when she is choose as a human forfeit.