Judy Holliday plays Billie Dawn, the "dumb blonde" girlfriend of Harry Brock (Broderick Crawford), a corrupt millionaire junk dealer. Brock, a man with social ambitions and a willingness to do anything to fulfill them, is embarrassed by Billie's crass behaviour and lack of social sophistication. So he arranges for her to take a crash course in "culture" from a young journalist (William Holden). Billie blossoms under his kind tutelage and becomes increasingly aware of her role as a pawn in Brock's crooked business deals. Brock is surprised and outraged when Billie suddenly refuses to cooperate any longer. This is a classic comedy with an unforgettable performance.