Killer Kid tells the story of Djilali, an orphan from Lebanon, recruited to be a soldier. He is sent to Paris on a secret mission, and, to help him "blend in," he is told to make friends with a poor Arab boy named Karim. Karim knows nothing of war - he loves rap music, skateboarding, cheeseburgers, and 16-year-old Isabelle. Soon, Djilali and Karim become close, vowing to remain friends "for better or for worse." But eventually Djilali must choose between his mission and the life of his friend.