In the 1960s, young women fainted during the shows of Quebec crooner Michel Louvain, who has been a heartthrob for 52 years. "Ladies in Blue" takes an affectionate look at the everyday lives of five women of different ages and walks of life who idolize the singer. While reflecting on Louvain's enduring career and celebrity, the film examines the universal lure of the unattainable that lies deep within each of us.

The film centres on Annie (Trudeau), the Canadian wife of wealthy businessman André Roussel (Falcon), who is sent by her husband on a vacation in the French Riviera. Her husband sends private detective Aldo (Lemaire) to follow her as he suspects her of infidelity; however, Annie and Aldo themselves begin a romantic relationship with each other.