Abel T. Léonard, Managing Director of Glacéco, a multinational refrigerator company, goes to Paris with his secretary to appoint the future European vice-president of his company. Among the candidates from Italy, England and Germany is the French Denis Bonneval. To influence him, the latter invites Abel and his secretary as well as the other competitors to his country house. The same day, Thérèse, his wife, a lawyer in need of clients, accepts the defense of the killer Stéphane Brévin, accused of having strangled eleven people. The murderer prepares his trial with the Bonnevals who pass him off as Thérèse's secretary.