This Best Short Subject Academy Award winning film begins in the spring of 1940, just before the Nazi occupation of the Benelux countries, and ends immediately after the Japanese attack on Pearl Harbor. It chronicles how the people of "Main Street America", the country's military forces, and its industrial base were completely transformed when the decision was made to gear up for war. Original footage is interspersed with contemporary newsreels and stock footage.

A wealthy banker wants to tear down a tenement slum to build a factory, but a charming girl who lives there begins to persuade him otherwise.

When a movie actor is shot and killed during production, the true feelings about the actor begin to surface. As the studio heads worry about negative publicity, one of the writers tags along as the killing is investigated and clues begin to surface.