A short time before she is to marry banker Ernesto Traversi, Angela Chiaromonte, the daughter of an Italian prince, meets soldier Giovanni Severi after he crashes his automobile into her father's chauffeur-driven car. Inspired by this chance encounter, the innocent and well-protected Angela drags her nursemaid, Mina, to the town carnival, where she again encounters Giovanni. Determined to impress the shy Angela, Giovanni takes her to a cafe and confesses that he has fallen in love with her. Although lovestruck, Angela tells Giovanni about her engagement to the proper, older Ernesto and later writes him a letter declaring the end of their flirtation. Six days before the wedding, however, Giovanni appears at a dance at Prince Chiaromonte's and, after sequestering Angela, forces her to admit that she loves only him. When the prince then catches his daughter kissing Giovanni, he denounces the soldier and orders him to leave. In spite of Angela's protests that Giovanni and she want to marry, the prince, whose own wife deserted him for another man and later committed suicide, insists that she wed Ernesto. Angela, however, refuses to obey her father and runs off to find Giovanni. On her way to Giovanni's residence, her automobile collides with her father's, and the prince dies instantly in the crash. Devastated by her father's death, Angela moves quietly to a small apartment with Mina but eventually is found by Giovanni. Although happy to see Giovanni, Angela is too grief-stricken to resume their romance and sends him away after a few minutes. Soon after, however, news of Italy's entrance into World War I reaches Angela, and before Giovanni is shipped to the front, she eagerly pledges her love to him. Months later, Giovanni, now an ace aviator, is shot down by a German airplane and is presumed dead. Racked with grief, Angela arranges with Father Saracinesca, a longtime friend, to enter a convent. While Angela studies to become a nursing nun, Giovanni recuperates on a German farm from injuries sustained during his crash. When he learns that the German army is in the area, he says goodbye to his benefactors and heads for the Swiss border. Giovanni is soon captured by the Germans, however, and is sent to a prisoner-of-war camp. After two years in the camp, Giovanni, who has been living in solitary confinement because of his repeated escape attempts, sneaks out during a cholera epidemic in a fellow prisoner's body bag. Giovanni flies a stolen German plane to safety, then begins his search for Angela. When he finally tracks Angela to a military hospital, he is stunned to discover that she is now a nun. Angela, too, is shocked by Giovanni's return but, in spite of her resurging passions, insists that her religious vows are unbreakable. Convinced that Angela still loves him, Giovanni tries to persuade her away from the church but, when he sees her praying during an air raid, realizes that she no longer belongs to him. Soon after Giovanni leaves the town, he is hit by German fire, and then dies in Angela's loving arms.