Chaya is a sixteen-year-old Jewish girl from Krakow working as a courier for the Akiva resistance movement in Nazi-occupied Poland. Because she speaks Polish-accented German and has fair hair and skin, she easily passes as a gentile. This allows her to move relatively freely outside the ghettos, where she steals supplies to distribute to trapped Jewish residents. Resourceful and deeply affected by the separation of her family, she pours her grief into fighting her oppressors.

Esther is a young, noticeably shy Jewish girl assigned to work alongside Chaya in the Akiva resistance group. Unlike Chaya, Esther possesses distinctively Jewish features and mannerisms, making it difficult for her to pass as a non-Jew in occupied Poland. She lacks field experience and struggles to adapt to the deception required for courier work, causing friction with her peers.

Yitzchak is Chaya's younger brother, twelve years old at the time their family is fractured by the German occupation. After his younger sister Sara is loaded onto a transport train to Belzec, Yitzchak disappears entirely. His unknown whereabouts haunt his parents and sister, driving their individual responses to the war.

Sara is Chaya and Yitzchak's youngest sibling. At only eight years old, she is taken from the Podgorze Ghetto and loaded onto a transport train bound for the Belzec extermination camp. Her removal shatters the Lindner family and serves as a major catalyst for Chaya joining the armed resistance.

Mrs. Lindner is Chaya's mother, formerly a homemaker in Krakow before the war. The trauma of losing her eight-year-old daughter to the transport trains and the simultaneous disappearance of her son leaves her completely broken. She refuses forged identification papers, choosing instead to remain in the ghetto in the desperate hope that her son might one day return to find her there.

Mr. Lindner is Chaya's father and a former shoe repair shop owner. Stuck in the Podgorze Ghetto with his deeply depressed wife, he focuses entirely on keeping her going. Rather than push his wife to escape with forged papers, he enables her belief that they are safer inside the ghetto walls.

Dolek is a high-ranking leader within the Akiva resistance movement. Because he has Polish features, he can travel across the country with less suspicion, allowing him to gather intelligence and coordinate different cells. He organizes major offensive maneuvers against the occupying forces and motivates the young fighters to secure their place in history.

Shimshon is a former Jewish scout leader who runs a farm with his wife, Gusta. As the occupation worsens, he uses the farm as a sanctuary for displaced youths and begins transitioning the scout group into an active resistance movement. He formally calls upon the youths to join the fight against the occupying forces.

Gusta helps run the agricultural property that serves as the initial safe haven for the Akiva scouts. She works alongside her husband to organize the displaced youths and transform their community into a functioning resistance cell.

Rubin is a slightly older boy serving in the same Akiva resistance cell as Chaya. He participates in the group's early supply raids and sabotage missions. Later, he connects with the partisans hiding in the forests, helping to bridge the gap between different factions of the resistance.

Jakub is a younger boy assigned to Chaya's resistance cell. He eagerly participates in the raids on German storehouses and trains, taking on dangerous positioning during the missions. His involvement in a botched raid creates a tense dynamic within the group.

Hanusia is one of the young girls working in Chaya's Akiva cell. During raids, she is usually stationed at the farthest endpoint to guard the wagons used to transport stolen supplies, playing a crucial logistical role in the group's covert operations.

Meriam is an experienced courier assigned to Chaya's Akiva cell. She participates in drop-point operations during the train robberies. Because of her expertise, she is sometimes pulled away by leadership for separate missions up north.

Fishel is a young boy living inside the Tarnow Ghetto who acts as an inside contact for the Akiva couriers. He quietly guides Chaya through the ghetto to the specific locations needed to complete her smuggling tasks.

Antek is a high-ranking, founding member of Akiva who is only a few years older than Chaya. When the group suffers heavy losses and structural collapse, Antek steps up to take control of the organization and coordinate its remaining agents.

Avraham is a starving teenage boy hiding in an abandoned building in the Lodz Ghetto. Having lost his entire family, he refuses to participate in forced labor. However, he firmly believes that killing soldiers is tantamount to murder and chooses to resist purely through his refusal to comply, placing his fate in God's hands.

Henryk is one of the three teenagers surviving in secret inside the Lodz Ghetto. Like his companions, he refuses to work for the occupying forces but also refuses to utilize violence to escape. He possesses crucial knowledge of the ghetto's layout, including fire escapes and munitions factory routes.

Wit is an older Polish man who drives a horse-drawn wagon. He represents the minority of Polish citizens who actively risk their own lives to help Jewish refugees. He uses quick thinking to defuse dangerous situations and utilizes his knowledge of the countryside to help couriers avoid military patrols.

Mordecai is the historical leader of the ZOB (Zydowska Organizacja Bojowa) in Warsaw. He successfully unites the fractured underground factions into a single cohesive defense force and spearheads the massive preparations to fight off the impending ghetto liquidation.

Tamir is an operational leader within the ZOB in Warsaw. He manages the induction of new fighters, assigns them to bunker-digging details, and coordinates tactical retreats and communications during skirmishes.

Rachel is a female leader in the ZOB who values the tactical experience of couriers from other cities. She interviews Chaya to learn from the failures of previous Akiva attacks and manages high-stakes supply logistics within the underground tunnel networks.

Rosa is an older Jewish woman taking shelter in the fortified bunkers of Warsaw. She acts as a medic for the young resistance fighters, offering them maternal care and a brief sense of comfort amidst the harsh realities of their situation.