 loggers are destroying the jungle near Tarzan and the family. The loggers are following the orders of Bob Markham who has the legal logging rights for this particular area of jungle. Tarzan confronts Markham and finds him to be a reasonable, family man with a daughter. They try to find a compromise but it doesn t quite hold and the logging continues. Tarzan is determined to protect his jungle but won t need to because the loggers begin to get sick and the professor fears he knows why...all the disturbing of the soil has released a dormant virus into the air. Tarzan and Markahm set off to find the ingredients for an antidote.