In the Secret of Dr. Kildare by Max Brand, Dr. Leonard Gillespie is about to start an important research project at Blair General Hospital to improve the use of a Sulfa drug, Sulfapyridine, as a cure for pneumonia with the help of his assistant, Dr. James Kildare. Paul Messenger, a Wall Street tycoon, asks for Gillespie's help in diagnosing the drastic, sudden personality changes that occur in his daughter Nancy. Gillespie assigns Kildare to pose as an old friend of the family to observe Nancy.