At the Belgian border, a group of young people engaged in various contraband traffic bother the customs officers.

Marguerite Le Goff has a sad destiny. Daughter-mother to a holidaymaker at the age of sixteen, she tried to earn a living in Nantes, but succumbed to the promises of the disreputable Pierre who had found her in a sailors' box. Deprived of her child, what would she do if good people didn't sympathize and her childhood friend Jean-Marie didn't take her with him?

As a favor to his grandmother, singer Rudy Hirigoyen agrees to sing incognito, under the name Romano, in the nightclub his cousin Gustave has just opened in a small seaside resort. The staff and musicians are students camping out in the pine forest near "L'Auberge Fleurie". Grandma has rented the apartment above the club to summer guests: Commandant Portafaux and his wife.

Fredo, a former gangster nicknamed "The Bluffer", has just been released from prison and is now thinking of going into the legal world with a friend. But his ex-partners are desperate to find him, to punish him for operating without their cooperation. His fortune is stolen and he is accused of a diamond robbery perpetrated by the old gang.