Syvia is a bright four-and-a-half-year-old girl whose comfortable early childhood is abruptly halted by the outbreak of World War II. After a failed attempt to relocate to Warsaw, she and her family are forced into the overcrowded, heavily guarded Lodz Ghetto. Stripped of the chance to attend kindergarten, she spends her days adjusting to the grim new reality of her surroundings. She relies on her vivid imagination and the protection of her family to endure the daily deprivations.

Isaac is a capable and observant father who previously worked as a successful salesman before the war. Stripped of his livelihood by systemic persecution, he takes on grueling physical labor as a flour delivery man within the Lodz Ghetto. He continuously demonstrates quick thinking and resourcefulness, carefully collecting spilled flour dust from his work clothes to help feed his starving family.

Haya is a deeply loving and altruistic mother forced to adapt to extreme poverty after enjoying a comfortable middle-class life. Inside the ghetto, she labors in a factory making women's underwear to secure a meager ration card. She quietly sacrifices her own health, frequently giving her inadequate food portions to her growing daughters.

Dora is Syvia's sister, eight years her senior. Forced to grow up overnight, she pretends to be fourteen instead of twelve so she can work long shifts in the ghetto's underwear factory. She bitterly misses her old school and friends but channels her energy into fiercely protecting and educating her little sister, using sticks in the dirt to teach her the alphabet.

Hava is a young girl living in the Lodz Ghetto and one of Syvia's closest playmates. She endures family tragedy early on when her brother falls ill. She represents the innocent children caught within the barbed-wire fences.

Itka is another young resident of the ghetto who befriends Syvia. She relies on her imagination to cope with their restricted lives, suggesting fanciful ideas like having tea with royalty during their doll games.

Uncle Hyman is a relative of the Perlmutter family. Like the rest of the adults, he faces the daily struggle to protect his loved ones and secure basic necessities within the heavily guarded walls.

Aunt Rose is a member of the extended Perlmutter family, navigating the severe food shortages and constant threats alongside her husband and child.

Mina is Syvia's cousin. As a child in the ghetto, she shares the exact same vulnerabilities as Syvia regarding the strict rules imposed by the occupying forces.

Uncle Haskel is another relative of Isaac and Haya. He experiences the same daily fears and harsh working conditions that dictate life for the adults in the enclosed city.

Aunt Hana is married to Uncle Haskel. She manages the difficult task of maintaining a household under conditions of severe rationing and limited resources.

Isaac is Syvia's young cousin, only three years old. Despite his very young age, the brutal environment forces him to learn unnatural behaviors, remaining completely silent to avoid drawing the attention of armed guards.

Rumkowski serves as the elder leader of the Jewish population in the Lodz Ghetto. He acts as the primary liaison between the imprisoned community and the occupying authorities, directly issuing decrees that heavily impact the residents' daily lives.