The Birthday.

The four sequences in the film cover four days in a life of young Warsaw lad in September 1938, 1939, 1943 and 1944. In the first sequence Jurek decides not to study in the Sorbonne but enlists in a Polish military school instead. In the second sequence the war starts and Warsaw is occupied. In the third sequence he works in the underground resistance. The final sequence takes place during the Warsaw uprising.