 In this remake of Universal s 1938 "The Crime of Dr. Hallet", two scientists, Dr. Paul Harris (Lowell Gilmore) and Dr. William Sommers (Peter Cookson), are seeking a cure for a jungle fever. Sommers dies after inoculating himself with a new serium. Gilmore, in order to continue to receive the financial backing that Sommers had, assumes his identity and carrys on the work with newly-arrived Dr. Mary Harris (Jane Wyatt.) Sommers widow Virginia (Julie Bishop) 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 serium.