Summer 1980. Louis is fifteen and has spent half of the summer shut away in his bedroom. Incapable of going out, he spends hours reworking a mural he has painted on one of his walls. Night and day, he listens intently to his neighbors' conversations on his walkie-talkie. Raphaël, Agnès, Antoine, Céline, he knows everything about the residents of his high-rise building, down to the intimate details of their sexual experiences that they innocently confide to each other. Louis is surprised by the feelings of desire that begin to stir in him for these seductive voices, these mysterious teenagers that he is yet to meet.