Two young models are murdered a few days apart. The first clues lead Gréco to the fashion magazine "Femmes" and its sultry photographer, John Devers, who likes very young girls. When a third young model from the magazine is murdered, the divisional commissioner puts Gréco on the sidelines and entrusts the case to a Parisian crime star. Offended to death, Gréco resigns. But she makes it a point of honour to find the murderer before anyone else. She leads the investigation from her hotel room, with her two assistants Max and Rose in a submarine at the police station.