During a summer assignment, Nobita must research the history of his town. He and Doraemon use a gadget called the Time Camera to take photographs of the town at various periods. In their final shot, they capture the legendary Japanese folk hero Momotaro pulling a cart filled with treasure. Later, Nobita's mother meets a foreigner who shows the children a small picture of a samurai‑clad figure. The image appears almost photographic, and the figure looks exactly like Momotaro. The foreigner inherited the picture from his ancestors and has come to Japan to discover its true origins. Nobita begins to suspect that Momotaro might have been a real...