In 1934, at the age of six, Marie-Laure LeBlanc lost her eyesight. Her father, Daniel LeBlanc, is a locksmith at the Museum of Natural History in Paris. He builds Marie-Laure a scale model of their neighbourhood to help her navigate, and she spends her days with him at the Museum, reading Jules Verne in Braille. But their peaceful life is upset by the German invasion, and they flee the Nazi occupation of Paris, taking refuge in the coastal town of Saint-Malo. Unbeknownst to Marie-Laure, the Museum has entrusted her father with an item from its collection. What Daniel LeBlanc does not know is if it is the real artefact, or one of the three duplicates that was made to serve as a decoy. Meanwhile, in Germany, Werner Pfennig is orphan who lost his mother to illness and his father to the coal mines of Zollverein. He has a passion for radios and math. When war comes, these skills draw him to the attention of the Reich, and he is selected to attend a special military prep school where talented young Germans are indoctrinated into National Socialism.