These familiar figures of the 20th century appear together in a film, which is like a summary of the modern history of the world, bringing together the changing and turbulent history of Europe, Asia and America. This film is "what are we fighting for". While Eurasia is experiencing the baptism of blood and fire in World War II, Americans still maintain their own way of life, and the war seems to be just news on the radio. It was not until the outbreak of Pearl Harbor that the United States realized that war had befallen the United States. Capra, the master of Hollywood movies, was the first successful person to emigrate to the United States to realize his dream. At the beginning of the twentieth century, he traveled from Italy to the United States, first Paramount, then Columbia, and became famous for his joining. An one-night affair brought him to the top of his Oscar dream. A few weeks after Pearl Harbor, Hollywood film director Frank Capra was suddenly sitting in the office of Marshal Marshall, the chief of staff of the U.S. Department of Defense. Capra had changed into a brand new military uniform and turned into a major. The marshal explained to him the intention of summoning him: the ratio of civilians to professional soldiers in the US army is about to reach 50 to 1.