In this remake of Universal's 1938 "The Crime of Dr. Hallet", two scientists, Dr. Paul Harris and Dr. William Sommers, are seeking a cure for a jungle fever. Sommers dies after inoculating himself with a new serum. Gilmore, in order to continue to receive the financial backing that Sommers had, assumes his identity and carries on the work with newly-arrived Dr. Mary Harris. Sommers widow Virginia also drops in and accuses Harris of murdering her husband. To prove his innocence, Mary, who is in love with him, inoculates herself with the Harris serum.