Dr. Jerry Flynn, Doc Jerry to his friends, the world's foremost authority on primate genetics, has been summoned to a secret jungle laboratory in the Congo where refugees from Nazi Germany are rumored to be crossbreeding apes with humans to create an improved Aryan race. The creatures--"Half and Halfs," part human and part ape--have escaped into the jungle and are raising havoc. The locals are frightened and jumpy. Doc Jerry has no choice but to help them out, though there is no easy solution. Should he capture the "Half and Halfs" and put them back in their cages in the lab? Should he ignore them and let nature take its course? Or should he simply kill them all, part human or not, and be done with them?