La moucharde stars Dany Carrel as a young miss who loves neither wisely nor well. Duped into a life of crime, Carrel remains on the wrong side of the Law because she's hopelessly in love with a two-bit crook. Soon she becomes as jaded and hardened as her criminal cohorts. When the police threaten to throw her in the Bastille, Carrel agrees to turn informer, with the expected disastrous results.