Franz Roberti (Charles Boyer) is a passionate and eminent musical conductor; Constance Dane (Katharine Hepburn) is an aspiring but unknown composer. She wants to see his concert, but it is all sold out. When she sneaks into his rehearsal he is smitten by her devotion and gets his orchestra to get it right as they play just for her. Constance marries Franz: he says she is “a most exciting creature” and she has been in love with him for a long time (i.e., “since late this afternoon”).
Not long after they get married Constance finds Franz having dinner with a female friend. So Constance responds by going out with her own friend, Johnny Lawrence (John Beal). Johnny wants to marry Constance, but she cannot forget her husband. Franz has been hitting the bottle and pretty much throwing away his career, although exactly which of his many sins is driving him to drink is not really clear. Fortunately, Constance has been working on her concerto.