 A subplot concerns the struggle for the love of the Spanish woman Juana (Loren) by the two male protagonists.The screen story and screenplay by Edna Anhalt and Edward Anhalt was loosely based on the 1933 novel "The Gun" by C. S. Forester.Earl Felton did an uncredited screenplay re-write, George Antheil composed the music score, while Saul Bass designed the opening title sequence.