Film examining the United States' role in World War II, which began with a surprise attack when, on the morning of 7 December 1941, a contingent of hundreds of Japanese bomber planes attacked Pearl Harbor in the most successful surprise attack in history. In less than two hours, they had destroyed or seriously damaged 347 planes and 18 ships of war. American casualties totalled over 3000. Four years later, President Harry S Truman decided to use the most advanced weaponry available against the Japanese: the atomic bomb. The 'Little Boy', with its core of uranium 235, was dropped over Hiroshima on 6 August 1945. The more sophisticated and more deadly 'Fat Man' was dropped over Nagasaki three days later. The bomb was ten feet long, five feet wide, 10,000 pounds, with plutonium at its core. Of the 286,000 people living in Nagasaki at the time of the blast, 74,000 were killed and another 75,000 sustained severe injuries. Shortly thereafter, the Japanese surrendered.