Francis Bosco, caretaker of a housing estate, is found murdered. According to initial findings, the victim was killed with an electric baton. The jogger who discovered the body explains to Alice that Bosco, a former gendarme, had been hired to ensure the security of the neighborhood. To do this, he had supervised the installation of surveillance cameras on every street corner. Alice and Marquand try to find out more about the victim's private life.
