Six-year-old Marie-Laure loses her sight to cataracts, and her father begins patiently teaching her to navigate the world.

A museum tour guide tells young Marie-Laure the legend of the Sea of Flames, a cursed diamond that grants its keeper eternal life.

Orphan Werner Pfennig finds a broken radio in a dump and repairs it, connecting the Children's House to the outside world.

Daniel LeBlanc builds a detailed scale model of their Paris neighborhood so blind Marie-Laure can learn to navigate independently.

Werner and Jutta secretly listen to a French professor's radio broadcasts about light, inspiring dreams of a life beyond the orphanage.

Werner is accepted into the elite Schulpforta military school, while a furious Jutta refuses to speak to him.

Marie-Laure and her father flee Paris on foot with thousands of other refugees as the German occupation begins.

Daniel LeBlanc is arrested by German police on his way back to Paris and transported to a prison work camp.

Madame Manec dies of pneumonia, leaving Marie-Laure and Etienne to face the German occupation alone.

American bombers destroy the Hotel of Bees, trapping Werner and his companions in the rubble-filled basement.

Sergeant Major von Rumpel enters the LeBlanc house and searches Marie-Laure's room for the hidden Sea of Flames diamond.

Alone in the attic with von Rumpel searching below, Marie-Laure reads Jules Verne's novel aloud into the radio transmitter.

Werner shoots von Rumpel and rescues Marie-Laure from her hiding place behind the attic wardrobe.

During a cease-fire, Werner escorts Marie-Laure to the grotto, where she drops the little model house into the sea.

Captured by the French resistance, Werner later wanders into moonlight outside the prisoner camp and dies on a land mine.

Marie-Laure LeBlanc loses her sight in childhood and must learn to navigate the world anew, while Werner Pfennig repairs a radio in a German orphanage and dreams of a life beyond the mines. Both children find hope in science and imagination as the shadow of war closes in around them. When Germany occupies France, Marie-Laure and her father flee Paris, and a precious cursed diamond from the museum travels with them into hiding. The war separates them from everyone they love, and the Allied siege of Saint-Malo traps them both inside the burning city. Werner ultimately risks everything to rescue Marie-Laure, returning the diamond to the sea before his own life comes to its quiet, moonlit end.

The headline events that drive Marie-Laure and Werner toward their fateful meeting.

Marie-Laure finally masters navigating her neighborhood from memory, and Daniel celebrates by swinging her in the falling snow.

Two older orphanage boys join the Hitler Youth, swagger around town, and destroy Jutta's drawings of Paris.

Fleeing Paris through the night, Daniel opens his rucksack and reveals he is carrying a diamond from the museum.

Werner climbs a twenty-five-foot ladder during the Schulpforta entrance exam and jumps without hesitation, impressing the examiners.

Dr. Hauptmann summons Werner to work in his private laboratory, and giant cadet Frank Volkheimer is assigned as Werner's protector.

Etienne shows Marie-Laure the hidden attic radio and plays gramophone recordings of his dead brother Henri's science lessons.

German authorities force Saint-Malo citizens to surrender all radios; neither Etienne nor Marie-Laure mentions the transmitter hidden in the attic.

Werner and Frederick visit Berlin during school vacation; Frederick secretly wears eyeglasses and shares a forbidden American bird book.

Werner throws cold water onto a bound prisoner; Frederick pours his bucket onto the ground and flatly refuses to participate.

Madame Manec forms the Old Ladies' Resistance Club, and the women begin sabotaging German positions around Saint-Malo.

Frederick is brutally beaten by the other boys with the commandant's approval, suffering permanent brain damage before being sent away.

After Madame Manec's death, Etienne creates a false back to the wardrobe and takes over her resistance radio broadcasts.

Werner's unit uses his transceiver invention to locate and kill partisan radio operators in Russia, burning the building with the bodies inside.

Volkheimer builds a barricade around Werner, then uses a grenade to blast open the basement stairwell and free them both.

Jutta and her son Max visit Saint-Malo following clues in Werner's belongings, and Jutta eventually meets Marie-Laure at the Paris museum.

Werner's path from gifted orphan to reluctant soldier is marked by small surrenders of conscience, beginning when older boys at the orphanage embrace Nazi ideology and ending when he watches his only friend Frederick destroyed by the school's brutality. In Saint-Malo, Madame Manec builds a quiet resistance from scratch, drawing Etienne out of his fearful isolation and into active defiance of the occupation. Werner's scientific talent is steadily weaponized by the Reich, as the transceiver he designed for Dr. Hauptmann becomes a tool for tracking and killing partisan radio operators across Europe. By the time the siege of Saint-Malo traps Werner in the basement, both his guilt and his buried humanity are fully primed for the moment of rescue. The thread continues past the war's end, when Volkheimer's quiet act of returning Werner's belongings eventually brings Jutta face to face with the blind woman her brother died saving.

The supporting moments that shape Werner's moral journey and the Saint-Malo resistance.

Daniel gives blind Marie-Laure an expensive Braille copy of Around the World in Eighty Days for her ninth birthday.

After repairing Herr Siedler's powerful radio, Werner returns to the orphanage and destroys his own illegal homemade shortwave radio with a brick.

Before Werner leaves for Schulpforta, Jutta confronts him and warns that attending the Nazi school will turn him into a bully.

Marie-Laure and her exhausted father finally reach Etienne's narrow house in Saint-Malo, where Madame Manec feeds them and Marie-Laure falls asleep at the table.

Von Rumpel threatens museum staff in Paris until they show him the locked box where the Sea of Flames is kept.

Etienne leaves a trail of seashells to his door and welcomes Marie-Laure, revealing a room full of radios, shells, and books.

Madame Manec challenges Etienne to broadcast resistance messages over the hidden radio, asking him if he wants to be alive before he dies.

Werner locates the partisan broadcaster and instantly recognizes the French professor's voice from childhood, deciding not to report the location.

German soldiers corner Marie-Laure inside the grotto; she finds the hidden resistance slip in her loaf of bread and eats it.

When Marie-Laure fails to return home, Etienne overcomes his agoraphobia and steps outside for the first time in over two decades.

Marie-Laure decodes the hidden clues in her father's letter and opens the model house, finding the Sea of Flames in her palm.

Trapped in the basement, Werner hears a girl reading French over his repaired radio and realizes she is in real danger.

Werner confesses to Volkheimer that he deliberately misled their unit about the source of the resistance radio broadcasts.

Werner and Marie-Laure spend the night talking and discover their shared childhood connection to the professor's radio broadcasts about light.

Elderly Marie-Laure walks through the Paris gardens with her grandson and imagines the dead as souls traveling on invisible waves of light.

From the moment Daniel gives Marie-Laure her first Braille book to the afternoon she imagines the dead drifting through the air like radio waves, the novel is built on revelations that change what characters believe is possible. Werner's decision to destroy his homemade radio after visiting Herr Siedler marks the first of many compromises with his conscience, each one nudging him deeper into the Reich's machinery. Etienne's transformation from agoraphobic recluse to active resistance broadcaster is triggered by Madame Manec's challenge and completed the day he forces himself outside to find Marie-Laure. The novel's climax pivots on two quiet acts of refusal: Werner choosing not to report the professor he recognizes, and Marie-Laure dropping the cursed diamond into the sea. These turning points converge in a single night of conversation between the two protagonists, revealing a connection that stretches all the way back to their childhoods.

The key decisions, discoveries, and emotional shifts that define each character's arc.