An unhappily married woman devises a scheme to get rid of her husband.
Denise, an orphaned girl, moves to Paris where she hopes to find work at her uncle's store. But the glamorous department store 'Aux Bonheur des Dames' across the street crushes all the little businesses around. She finds a position there.
Willy Ferrière is a gambler living beyond his means, and his mistress is as greedy as he's dead broke. One day, he says out of loud in a a Montparnasse café that he would give 100,000 francs to get rid of his wealthy aunt so he could claim his inheritance. Someone secretly lets Willy know it's a deal. The old lady is murdered, and a low-life criminal is manipulated to be the perfect suspect. But Superintendant Maigret feels something is wrong.
