In Los Angeles, Theodore Twombly is a lonely, introverted man who works for a business that has professional writers like himself compose letters for people who are unwilling or unable to write letters of a personal nature themselves. Unhappy because of his impending divorce from childhood sweetheart Catherine, Theodore purchases a talking operating system (OS) with artificial intelligence, designed to adapt and evolve. He decides he wants the OS to have a female voice, and she names herself “Samantha”. Theodore is fascinated by her ability to learn and grow psychologically. They bond over their discussions about love and life, such as Theodore’s avoiding signing his divorce papers because of his reluctance to let go of Catherine. Samantha proves to be constantly available, always curious and interested, supportive and undemanding.