The movie is based on the book of the same title written by Ernest Hemingway, however, much was changed to suit the movie version. Beside Bogart and Bacall, the cast includes Walter Brennan, Dolores Moran, Sheldon Leonard and Hoagie Carmichael.
Bogart plays fishing captain Harry Morgan who rents his boat out to customers who want to go fishing. Morgan's last customer owes him $825. but is shot and killed before he can pay Harry Morgan.
Morgan gets mixed up with the law when he is asked to transport two members of the French Resistance. At first Morgan refuses but then reluctantly accepts the job because he needs money.
Hoagie "Stardust" Carmichael plays Cricket the piano player.
Lauren Bacall was only 19 years old when she played opposite Humphrey Bogart who was 25 years older than she was. Bacall was very inexperienced in the area of relationships between a man and a woman and was quite innocent, but had to play a sophisticate in the movie.
Harry Morgan does end up falling for Slim.