In occupied Rome in 1944, German Schutzstaffel troops are trying to arrest the engineer Giorgio Manfredi, a Italian Communist Party and a leader of the Italian resistance movement against the German Nazis and Italian Fascism, who is staying in a rooming house. The landlady warns him in time of the Germans' arrival, so that he can elude them by jumping across the rooftops. He goes to the home of another Resistance fighter, Francesco. There he encounters Pina who lives in the next apartment. Pina is Francesco’s fiancée, and is visibly pregnant. She first suspects Giorgio of being a cop and gives him a rough time, but when he makes it clear he is not, she welcomes him into Francesco’s apartment to wait for him. With Pina’s help (she is also part of the Resistance), Giorgio contacts Don Pietro Pellegrini, a Catholic priest who is also helping the Resistance, and asks him to transfer messages and money to a group of Resistance fighters outside the city as Giorgio is now known to the Gestapo and cannot do it himself.