Les Diables (The Devils) chronicles the struggle of an autistic girl and her brother trying to survive without their parents. Chloe (Adele Haenel) is 13, and has been profoundly damaged from a life of abandonment -- so much so that she refuses to be to be physically touched, and never speaks. Her brother, Joseph (Vincent Rottiers), despite being slightly younger, has taken a fiercely protective stance with his sister. Street-smart and wiser than his years, Joseph hopes that they'll eventually find a family who will take them both in. Though their situation forces them to steal, the authorities catch them and leave the two siblings inside of a home for disturbed youth. At first, Joseph tries to escape, but puts his plans on hold when it looks as if a doctor is making progress with Chloe. Eventually, however, fights with the other orphans and a shocking piece of news force the children to go on the run once more.