Young Helen Keller (Patty Duke), blind and deaf since infancy due to a severe case of scarlet fever, is frustrated by her inability to communicate and subject to frequent violent and uncontrollable outbursts.
Unable to deal with her, her terrified and helpless parents contact the Perkins School for the Blind for assistance. In response, they send Anne Sullivan (Anne Bancroft), a former student, to the Keller home as a tutor. A battle of wills ensues as Anne breaks down Helen's walls of silence and darkness through persistence, love, and sheer stubbornness.
In the midst of the battle, Anne ultimately teaches Helen to make a connection between her hand signs and the objects in Helen's world for which they stand.