Draper Kauffman waits at the Pentagon to deliver an important message in a sealed envelope to the Admiral, Randall Jacobs. American forces have begun to assemble in preparation for the land invasion of Japan that is bound to begin sometime in November. General MacArthur predicts that the invasion will be one of the greatest losses of life in military history, likely costing the lives of half a million soldiers.

In the city of Hiroshima, Hideko Tamura has managed to get a letter back to her parents, telling them how miserable she and the other children are, and that they want to return home. She and a friend have hatched a plan to write their uncensored letters and sneak off to mail them on their own, rather than giving the letters to their caretakers to mail for them. Hideko and her friend Miyoshi receive word, and finally—on August 4th—are greeted by their mothers, who have come to take them home. Staying in town that night, they all agree to return to Hiroshima the next morning.

On Tinian, meanwhile, the bombing crew has just landed after a successful test run. Tibbets gathers his men together at 3 p.m. that afternoon and briefs them on the final details of what they are really all there to do: “The bomb you are going to drop is something new in the history of warfare.