Humphrey Bogart plays Rick Blaine, the American expatriate owner of an upscale club and gambling den called "Rick's Cafe Americain" in the Moroccan city of Casablanca, which attracts a mixed clientele of Vichy French and Nazi officials, refugees and thieves.
Rick is a bitter and cynical man who professes to be neutral in all matters, but he does not bother to hide a strong dislike for his fascist customers.

The score was written by Max Steiner, who was best known for the musical score for Gone with the Wind. The song "As Time Goes By" by Herman Hupfeld had been part of the story from the original play; Steiner wanted to write his own song to replace it, but had to abandon his plan because Bergman had already cut her hair short for her next role and could not re-shoot the scenes which incorporated the song. So Steiner based the entire score on it (and "La Marseillaise"), transforming them to reflect the changing moods of the movie.