After finding Marie-Laure in the grotto, Etienne tells her that he’s forced her to take on too much danger—from now on, she’s not allowed to go outside. Etienne will pick up the loaves as well as making the radio broadcasts.
Etienne’s new sense of protectiveness for Marie-Laure is a sign of how much has changed in recent months, and how he truly feels like a father to her now.
Marie-Laure notices that she and Etienne have barely any food left to eat—the war has taken a toll on Saint-Malo. She remembers the curse of the Sea of Flames, and the legend that says it kills everyone in the owner’s life, while leaving the owner unharmed. She also remembers what her interrogator in the grotto asked her: he wanted to know if Marie-Laure’s father was carrying anything for the museum. Finally, Marie-Laure remembers the letters her father sent her. In one letter, he told her to look in the house “inside the house.” Suddenly, it becomes obvious to Marie-Laure what this means. She rushes to the model of the city of Saint-Malo that her father designed, picks up the model of Etienne’s house, and finds a “pear-shaped stone inside.”
At this point in the story, the German war effort has deteriorated to the point where the Germans are running out of supplies, and so the occupied French are starving as well. Significantly, it’s only at this time that Marie-Laure remembers the diamond that kills everyone in its owner’s life. While von Rumpel is obsessed with the Sea of Flames, it’s fairly unimportant to Marie-Laure—she has always assumed that the best thing to be done with it would be throwing it back into the sea—which explains why she has taken so long to solve her father’s riddle. Her blindness to the stone’s beauty may contribute to this, but Marie-Laure seems like a rare character to be so immune to the seductions of the diamond