Colette is an 89-year-old accomplished jewel thief living in Boston, Massachusetts. Taught the family trade by her mother in 1930s Paris, she operates under a strict code of stealing only from the cruel to fund charitable causes. She volunteers at the Boston Center for Holocaust Education, which she anonymously founded. Despite her age, she remains sharp, stylish, and deeply protective of her chosen family.

Annabel is an Englishwoman from West Yorkshire who married a French schoolmaster and relocated to Paris. She claims descent from Robin Hood and actively practices jewel theft to redistribute wealth from the cruel to the needy. When the Nazi occupation begins, she channels her skills into funding the French Resistance. She is fiercely devoted to her daughters and believes strongly in fighting injustice.

Lucas is the director of the Boston Diamond Museum. He is a widower raising a college-age daughter, Millie. He demands ethical sourcing for the museum's gems. He finds himself caught between his professional duties, his family loyalties, and Aviva's inquiries into a mysterious bracelet.

Aviva is a 38-year-old attorney living in Boston. She lost her mother at age 18 and views Colette as a surrogate parent who provided stability during her grief. She volunteers at the Boston Center for Holocaust Education to honor her late mother. Her strict legal ethics often clash with the unconventional realities of Colette's life.

Marty is a Boston jeweler who inherited his family's diamond exchange business. He operates as a fence for Colette, selling her stolen goods. He has known Colette since 1952 and maintains a steady, reliable presence in her life. He supports her philanthropic missions and views her actions as morally justified despite their illegality.

Liliane is Colette's younger sister, growing up in World War II-era Paris. She looks up to Colette and takes comfort in the family stories of Robin Hood and the warning cry of an eagle. The chaos of the July 1942 roundup in Paris deeply impacts her early childhood.

Daniel is the son of a Parisian diamond merchant, born a twin in 1927. In the present day, he volunteers with a Holocaust education organization in New York City. He contacts Colette and Aviva after recognizing a museum piece that traces back to his family's lost legacy. He carries the emotional weight of surviving his family members.

Hélène is a Jewish mother living in Paris. She possesses a unique pair of diamond bracelets that resemble a butterfly when joined. She refuses to flee to the Free Zone, preferring to face the occupation in Paris. She shares a close bond with Annabel over their work and motherhood.

Salomon is a Jewish diamond merchant living in Paris. He celebrates the birth of his twins by commissioning pieces that are beautiful individually but stronger together. His family is targeted during the 1942 roundups by German officials.

Roger is a French schoolmaster married to an Englishwoman. He strongly objects to his wife's jewel thievery, creating friction in their household. He struggles to comprehend the full danger of the German occupation, initially believing the propaganda about labor camps.

Frédéric is a broker in Paris who fences stolen jewels for Annabel. He and his wife Marie act as a safety net for Colette when her parents are taken away. He defends Annabel's actions as a genuine attempt to make a difference in the world.

Hubert is a 102-year-old man living in a memory care facility in Braintree, Massachusetts. Originally from Paris, he emigrated to the United States after World War II. He possesses one half of the Rosman butterfly bracelet but becomes hostile when questioned about its origins.

Tristan is a young Jewish boy living in occupied Paris. He wears a yellow star on his coat and misdirects a pursuing officer to protect Colette. He leaves poetic notes for Colette in a hidden brick courtyard, adopting a romantic pseudonym from medieval literature.

Guillaume is a French police officer working in occupied Paris. He knows the Marceau family through his previous connection to Roger. He balances his police duties, his wife's desires, and his own sense of right and wrong.

Bill is Lucas's elderly grandfather living in the Boston area. He relies on a walker and holds deep bitterness toward Hubert Verdier. He discourages Aviva and Colette from investigating the history of the diamond bracelet, insisting that the past should remain buried.

Möckel is a German Nazi official operating in occupied Paris. He actively participates in the roundups of Jewish citizens and uses his position to confiscate valuable jewelry for personal gain. He presents a constant, terrifying threat to the families in Colette's neighborhood.

Known as The Peacock, Le Paon is a pediatrician who organizes an underground network in occupied Paris. He works to smuggle vulnerable people, including children, out of the city to save them from deportation. He accepts illicit funds from Annabel and later Colette to finance these operations.

Leo is Annabel's brother. He shares the Clement family tradition of thievery and fully believes in their supposed descent from Robin Hood. He eventually brings Colette to live with him in England before they relocate to the United States.