A girl named Riley Andersen is born in Minnesota and within her mind, five personifications of her basic emotions—Joy, Sadness, Fear, Disgust, and Anger—gradually come to life and influence her actions via a console in her mind's Headquarters. As she grows up, her experiences become memories, stored in colored orbs, which are sent into long-term memory each night. Her five most important "core memories" (all of which are happy ones) are housed in a hub that powers "islands", each reflecting an aspect of her personality. In Headquarters, Joy acts as a de facto leader to maintain Riley's cheerful childhood, but since she and the other emotions do not understand Sadness' purpose (not even Sadness herself), she frequently tries to keep Sadness away from the console.