In June 1940, Isabelle Rossignol chafes under the rigid etiquette lessons at her finishing school. During an exercise in peeling an orange with proper utensils, Isabelle’s impatience and sharp retorts provoke Madame Dufour, who sends Isabelle to the headmistress with the message that their “experiment” is finished.

In Madame Allard’s office, Isabelle argues that the school’s lessons are meaningless compared with the looming war. Pressed about her history of expulsions and her age, Isabelle admits her father has long tried to be rid of her and blurts out her bitterness over losing her mother and then her father’s affection. Madame Allard expels Isabelle immediately, telegrams Isabelle’s father, and sends Isabelle to Paris by train.

At the Gare de Lyon, Isabelle reunites with her father, hoping to be welcomed. Instead, he greets her with irritation about yet another expulsion, but he takes her with him, offering no comfort and no real choice. Isabelle moves into his apartment and, within a week, works in his cramped bookshop while sensing he still wants her gone.

On a hot day outside Paris, Isabelle spars with Christophe during a picnic, insisting women can help in war while Christophe dismisses the idea. Isabelle drives them back into the city and notices unusual wartime activity—lorries, gendarmes, sandbags, and treasures being moved from the Louvre—before she returns to her father’s shop.

At the bookshop, a panicked crowd surges through the streets with news that the Germans are coming into Paris. Isabelle’s father locks up and forces their way home through chaos and congestion. That night, German planes bomb the city; Isabelle and her father shelter with neighbors in the cellar through the raid. Afterward, Isabelle insists Paris won’t fall, but her father’s silence and grim warnings underscore how real the danger has become.