The Murder of Dr. Harrigan is based on a "Nurse Sarah Keats" mystery novel by Mignon Eberhardt. The middle-aged protagonist of the novel has been transformed into pretty, young nurse Sally Keating (Kay Linaker), in love with handsome doctor George Lambert (Ricardo Cortez). The founder of the hospital where Sally works disappears while en route to the operating room. Not long afterward, chief surgeon Dr Harrigan (John Eldredge) is mysteriously murdered by?whom? The key to the mystery is the formula for a revolutionary new anesthetic -- and there's plenty of suspects (including the perennial Mary Astor), motive and opportunity. Nurse Keating does a little mental "bypass surgery" on the police and figures out the mystery herself.