As a child, Jane Hudson was a pampered vaudeville star known to the world as Baby Jane while her younger sister, Blanche, led life in her considerable shadow.
Decades pass and Blanche becomes a beautiful, talented movie idol and Jane a has-been. When a car accident leaves Blanche in a wheelchair, Jane sees her opportunity to regain power and assumes the role of caretaker.
Her newly gained dominance completes the transformation of the sugar-sweet child star into a nightmarish caricature of Baby Jane.
As she does everything she can to make her sister’s life a living hell, Jane plots a comeback, aided by shifty musical director Edwin Flagg.