The film tells a wonderful adventure about the complex emotions in the mind of Riley, a little girl who has just entered adolescence. At the headquarters of her brain, a sudden demolition is taking place to make room for unexpected new emotions. The emotional friends Lele (voiced by Amy Poehler), Sadness (voiced by Phyllis Smith), Anger (voiced by Lewis Black), Fear (voiced by Tony Hale) and Disgusted (voiced by Liza Lapira), who have always cooperated with each other in a tacit way, are overwhelmed by the sudden arrival of the new emotion Jiao Jiao, and she does not seem to be alone.