When a cold medicine causes Sach to be able to smell diamonds, he and the rest of the Bowery Boys are induced by a diamond dealer to accompany him to Darkest Africa in search of a legendary cache of them.

During WWII, when an allied bomber is shot down over Germany, the five surviving crew are captured but cleverly escape detention after learning German secret information and knocking out a Nazi major. With the angry major in hot pursuit, aided by military personnel, Gestapo agents and Hitler-loyal citizens, the five wend their way across perilous Germany, intent on reaching the UK with the secrets they have learned.

A woman leads an expedition into a remote jungle to find her long-lost brother, but instead finds a mad scientist who has created a fungus monster that feeds on the local inhabitants.