Jenny Lamour (Delair) wants to succeed in the theatre. Her husband and accompanist is Maurice Martineau (Blier), a mild-mannered but jealous man. When he finds out that Jenny has been making eyes at Brignon, a lecherous old businessman, in order to further her career, he loses his temper and threatens Brignon with death. Despite this, Jenny goes to a secret rendezvous at Brignon's apartment, who is murdered the same evening. The criminal investigations are led by Inspector Antoine (Jouvet).