The film begins by describing the difficulties the civilian population posed during the Battle of Saipan including the famous mass suicide of Japanese who believed the US would torture them. As the Marianas campaign progressed though, the Marines learned to use the Intelligence Division (ID) to handle the Japanese civilians, and by the time the Marines reached Okinawa, the ID had become a routine part of the operation. The Marianas and Okinawa, pre-war Japanese possessions, had large Japanese civilian populations at the time of their occupation, whereas other islands, like Tarawa, Guam or Iwo Jima, were either uninhabited by civilians, or only by indigenous civilians.