A girl named Riley is born in Minnesota and, in her mind, at different points in her life, five living emotions are created: Joy, Sadness, Fear, Disgust and Anger. Each emotion has a defined purpose in Riley's life: Joy attempts to keep her happy, Anger keeps her life fair, Disgust keeps her from being poisoned both physically and socially and Fear keeps her safe. Sadness, however, doesn't think she has a purpose in her mind, or that of the other emotions, and is ignored as a result.