Nagasaki Journey tells the story of three people who witnessed the aftermath of the atomic bombing: Sumiteru Taniguchi, who was delivering mail on his bicycle when the bomb was dropped; Victor Tolley, a veteran of the US Marine Corps, part of the American occupation of Japan; and Itsuko Okubo who searched the ruined city for her missing son.

The film features extremely rare footage of the atomic bombing, both black-and-white and color.

Also included is a selection of stills taken the day after the bombing by Japanese photographer, Yosuke Yamahata — by far the most complete record of the immediate aftermath of the Nagasaki bombing that exists. They are used with the kind permission of his son and copyright holder, Shogo Yamahata.