Auguste scouts the cliffs and discovers a narrow cavern between two granite boulders high above the shore. Though Marguerite initially fears the dark, cramped space and worries about being trapped, she accepts that they have no timber for a proper shelter and recognizes that even a cave they call their own is preferable to her former life. Damienne, however, refuses to enter, declaring she would rather die in the fresh air.

As September brings a brilliant but short-lived autumn, the three carry their belongings up the steep slope. While working, Auguste and Marguerite share wishes of home comforts and lost orchards. Marguerite covets the strange black berries growing on the island, but Damienne forbids her from eating them, fearing they resemble belladonna.

They settle into the cave, sweeping it clean, building a pallet from the virginal's crate, and arranging their featherbed. The ruined virginal becomes an altar topped with the picture of the Virgin, which moves Damienne to tears of joy. Eventually Damienne too enters and sleeps with them. Because the trunks cannot fit inside, Auguste buries them nearby as makeshift cellars, organizing tools, linens, and powder, while keeping weapons just inside the cave entrance.

On Sunday, Auguste reads the miracle of loaves and fishes. Famished, Marguerite goes to fetch water and, overcome by craving, finally tastes the forbidden berries. They are bitterly tart; she spits them out and collapses, certain she has been poisoned. Auguste finds her and brings her back, terrified.

Damienne examines Marguerite and concludes the berries have not poisoned her—rather, hunger and fear are making her ill. She silently signals Auguste to the truth Marguerite cannot voice: Marguerite is pregnant, and her strange cravings stem from carrying a child.