Helen Keller, left blind and deaf after a debilitating illness as a baby, comes to love and rely on Annie Sullivan who teaches Helen many things and helps her become an inspiring and extremely motivated individual.
As revealed in The Miracle Worker, Annie's own life up to the point where she arrives at the Keller's home, at age twenty, has been difficult. She and her brother, Jimmy, were sent away after their mother's death and their father's abandonment. Annie promises to care for a sick Jimmy but he dies, for which Annie never forgives herself. Her own vision is seriously impaired, from having contracted an eye disease and she has various operations to partially restore her sight.
She is fortunately sent to The Perkins' Institute for the Blind and learns valuable lessons that she can pass on to Helen. She sees Helen as her opportunity to atone for not having cared sufficiently for Jimmy. She is patient and her stubbornness is equal to Helen's belligerence and the two become a formidable pair. This helps Annie deal with the loss of Jimmy, something that troubles her for many years.