By chance, Lenny, a young children's book author, discovers a roll of film in an old camera. Curious, he has it developed and is astonished to find that the pictures must have been taken in Prague in 1968, towards the end of the Prague Spring. One of the photos shows a young woman. To find out more about her, Lenny publishes it in a Prague daily newspaper. The effect is disastrous: his family's house is broken into and his father is murdered. Lenny is certain that there is a connection, because the photos have also disappeared. But neither his sister Isabell nor the police believe him. Shortly afterwards, he receives an anonymous letter containing only a Prague address. With this vague clue, Lenny sets off for the Czech capital.