Jacques Austerlitz, the main character in the book, is an architectural historian who encounters and befriends the solitary narrator in Antwerp during the 1960s. Gradually we come to understand his life history. He arrived in Britain during the summer of 1939 as an infant refugee on a kindertransport from a Czechoslovakia threatened by Hitler's Nazis. He was adopted by an elderly Welsh Nonconformist preacher and his sickly wife, and spent his childhood near Bala, Gwynedd, before attending a minor public school. His foster parents died, and Austerlitz learned something of his background. After school he attended university and became an academic who is drawn to, and began his research in, the study of European architecture. After a nervous breakdown, Austerlitz visited Prague, where he met a close friend of his lost parents, Vera, who often took care of "Jacquot" when his parents were away. As he speaks with her, memories return, including French and Czech expressions she taught him. The elderly lady tells him the fate of his mother, an actress and opera singer who was deported to Theresienstadt concentration camp. From Prague, Austerlitz travels to Theriesenstadt, and after returning to England via train, with an emotionally difficult journey through Germany, manages to obtain a 14-minute video compilation of highlights from Theresienstadt. Ein Dokumentarfilm aus dem jüdischen Siedlungsgebiet, the 1944 Nazi propaganda film, in which he believes he recognizes his mother. Vera, however, dismisses the woman from the documentary. Instead, she confirms the identity of Austerlitz's mother in a photograph of an anonymous actress which Austerlitz found in the Prague theatrical archives.
The novel shifts to contemporary Paris as Austerlitz seeks out any remaining evidence about the fate of his father. He meets up with the narrator and tells him of his first sojourn in Paris, in 1959, when he suffered his first nervous breakdown and was hospitalized; Marie de Verneuil, a young Frenchwoman with whom he became acquainted in the library, helps nurse him back to health. Sebald explores the ways in which collections of records, such as the Bibliothèque nationale de France or National Library of France, entomb memories. During the novel the reader is taken on a guided tour of a lost European civilization: a world of fortresses, railway stations, concentration camps and libraries.