Jenny Lamour wants to succeed in music hall. Her husband and accompanist is Maurice Martineau, a nice but jealous guy. When he knew Jenny is making eyes at Brignon, an old businessman, in order to get some engagements, he looses his temper and threatens Brignon with death. But Jenny went anyway to a rendez-vous at the old man's, who is murdered the same evening. The criminal investigations are lead by Inspector Antoine..