A contingent of Italian prisoners of war arrive on a train from Germany after World War II to Turin. The city where Ernesto (played by Nazzari) lives has been bombed, his mother is dead and his sister has gone missing. State help for returning veterans is scant and bureaucracy rampant. Ernesto tries to get an honest job, but fails. After finding a lost purse and meeting the dangerously seductive Lidia (played by Anna Magnani), Ernesto discovers the whereabouts of his lost sister (played by Carla del Poggio), who has turned to prostitution to survive during the war years. He unwittingly causes her death, kills her pimp, escapes capture with Lidia's help and joins her gangster band.