Isabelle Castro, the star of a night time show on Radio France, is dead. Assassinated by a psychopath. Because her voice tweaked his desire. Because he needed to destroy her. Because she was the seventh in his series. For three years, Commander Alex Bruce has been tracking the psychopath rapist and killer of seven women, nicknaming him "Vox". Obsessed by the killer, he gets help from Martine Lewine, cop and sharpshooter whose magical voice could overcome the crazy man. She will serve as bait.