Television reports that the shuttle “Columbia” has suffered an accident while returning to earth after a lunar expedition. In the news there is a drawing that one of the astronauts had brought: the terrestrial globe seen from space. Daniel, a boy who lives in Prague, recognizes the drawing and believes that there are several similar ones in his father's storage room. Indeed, there he finds a box with prints and notebooks signed by a certain Petr Ginz.

Petr was a boy who probably lived in that house in 1941 when the Nazis occupied the city. Daniel, who is the same age as Petr, reads in disbelief what life was like on the streets he walks through. The voices of the two boys begin to merge and the boundaries between the present and the past seem increasingly blurred.

Daniel wonders what to do with the testimony he has found by chance, whether there will be any survivors of that Jewish family to whom he can give Petr's belongings, or how to preserve that piece of history.