The Secret Of Dr. Kildare is the third entry in the highly popular Dr. Kildare series, which went on to spawn fifteen sequels over the '30s and '40s and a groundbreaking 1960s television series. In this outing, young Dr. Jimmy Kildare, played by series staple Lew Ayars, is recruited by his cancer-stricken mentor Dr. Gillespie (screen legend Lionel Barrymore) to assist in a pneumonia study.

After the overworked Gillespie collapses from exhaustion, Dr. Kildare finds himself juggling the pneumonia study and a young heiress's case of hysterical blindness. The stakes are high as the doctor attempts to restore sight to the young beauty, whose family fortune could help fund Gillespie's studies and cure pneumonia. The Secret of Dr. Kildare proves to be the crown jewel of the Dr. Kildare series.

Dr. Kildare (Lew Ayres) has all that he can handle when his mentor Dr. Gillespie (Lionel Barrymore) collapses from exhaustion while trying to find a cure for pneumonia. Knowing his condition could only get worse if he continues, Dr. Gillespie calls on Dr. Kildare to help with research while the elder is in recovery. What Dr. Gillespie doesn't know is that Dr. Kildare is already busy treating a woman with psychosomatic blindness while trying hard to cover his big secret.