Enemy agent Janos Passik is preparing to train 200 foreign agents to infiltrate the U.S. and engage in some form of bacteriological warfare. The team figures out that Passik has created a replica of a ""typical American town"" so as to train his agents to learn how to blend into American society. Rollin, Cinnamon, Barney, and bacteriologist Rogr Lee replace the new group of recruits and must then find their way to the research lab. They soon realize that the American-trained agents will be infected with a highly contagious plague and then sent into American to kill millions. The group must not only destroy the plague samples but make sure that Passik and his superiors do not find out that the destruction was deliberate.