Alina is a teenager growing up on a modest family farm in Trzebinia, Poland. Initially sheltered and romantic, she faces severe hardships when the Nazi occupation begins. In the contemporary timeline, she is Alice's beloved grandmother, affectionately called Babcia. She urgently requests her granddaughter's help to resolve a family secret.

Alice is a thirty-something stay-at-home mother living in Winter Park, Florida. She feels burned out and emotionally distanced from her busy husband. She devotes her energy to managing the vastly different needs of her two children. She relies heavily on the emotional support of her grandmother, which prompts her to reluctantly travel to Poland to uncover a mystery from the 1940s.

Tomasz is the intelligent son of Trzebinia's respected local doctor. He is deeply devoted to Alina and dreams of becoming a doctor himself. When the war breaks out, he uses his fluency in German and his medical background to assist the Polish underground. He takes extreme personal risks to scavenge for food and hide Jewish refugees in the woods.

Wade is a research executive specializing in nanotechnology. He spends long hours at the office and leaves the bulk of the domestic responsibilities to Alice. He believes his wife overprotects their son Eddie. This disagreement creates friction in their marriage, though Wade steps in to manage the household when Alice leaves for Europe.

Eddie is Alice and Wade's seven-year-old son. Diagnosed on the autism spectrum, he is nonverbal and uses an iPad application to communicate his needs. He relies on strict routines and his mother's constant presence to feel secure in his environment.

Callie is the ten-year-old daughter of Alice and Wade. Precocious and academically gifted, she takes advanced classes and shows a strong sense of self-confidence. She occasionally exhibits insensitivity regarding her brother's developmental differences.

Julita is Alice's mother and Alina's daughter. She is a highly successful circuit judge living in Florida. Practical and career-oriented, she views Alice's decision to drop out of journalism school and become a stay-at-home mother as a personal disappointment.

Saul is an extraordinary pediatric surgeon from Warsaw. After the Nazis invade, he and his family face persecution and are forced into the ghetto. He relies on the Polish underground and Tomasz's intervention to seek shelter in the countryside near Trzebinia.

Eva is Saul's wife. She endures the brutal conditions of the ghetto and the terrifying escape to the countryside while heavily pregnant. She lives hidden in a tiny room on a neighboring farm and relies on scavenged food to survive.

Tikva is Saul and Eva's infant daughter, born while the family is in hiding. Her fragile condition shocks Alina and opens her eyes to the severe reality of the occupation.

Emilia is Tomasz's younger sister. As a child when the war begins, she struggles to understand the sudden violence and hatred of the occupation. Decades later, she holds the key to the historical events that Alice travels to Poland to uncover.

Zofia is a licensed guide and translator hired by Wade to assist Alice during her trip to Poland. She helps search municipal records and local geography. She translates documents as Alice investigates her grandmother's past.

Dr. Slaski is Tomasz and Emilia's father. As the most prominent doctor in Trzebinia, he represents stability and respect in the community. The occupying Nazi soldiers execute him in the town square as a demonstration of their power. This public violence leaves his family devastated.