Margaret is a tall, skinny twelve-year-old girl living in College Hill, Maryland. She considers herself a fearful person who worries about breaking the rules, getting blood poisoning, or crossing paths with local bullies. She relies heavily on her older brother Jimmy for protection and her bold friend Elizabeth for confidence. As she discovers hidden truths about the people in her town, Margaret's unquestioning acceptance of societal norms begins to fracture.

Elizabeth is Margaret's bold, blonde, and blue-eyed best friend. She is fiery, impulsive, and deeply patriotic. She wholeheartedly believes in the righteousness of the war effort and despises anyone she views as shirking their duty. Her dominating personality often forces Margaret into risky situations, and her fierce hatred of local bully Gordy Smith leads the girls into dangerous territory.

Gordy is the aggressive class bully who terrorizes Margaret and Elizabeth. He lives in a worn, shabby house and wears dirty clothes, earning the scorn of the College Hill community. Despite his hostile exterior and quick temper, he quietly carries the heavy burden of his family's dark reality and fiercely guards a secret hidden in the nearby woods.

Stuart is Gordy's older brother, a gentle, poetry-loving young man who deserted the Army due to his pacifist beliefs. Sickly and unsuited for combat, he believes that war and killing are fundamentally wrong. His illicit presence in town challenges the patriotic certainties of the community and forces the children who discover him to question their own worldviews.

Barbara is a young war widow raising her baby alone after her high-school sweetheart husband was killed in action. She is compassionate and hates the violence of the war, openly stating she values human life far more than military medals. Her lifelong friendship with Stuart pulls her into a dangerous conspiracy.

Mr. Smith is the violent, alcoholic patriarch of the Smith family. Known in town for his public drunkenness and fighting at the Starlight Tavern, he terrorizes his wife and children behind closed doors. His brutality forces his children to rely entirely on each other for survival while the neighborhood looks the other way.

Jimmy is Margaret's beloved older brother, currently serving overseas in the Army. He is an artist with a gentle nature, known for protecting Margaret from monsters under her bed and defending vulnerable children from bullies. His sanitized letters shield his family from the grim realities of the front lines.

Mrs. Baker is a traditional homemaker who spends her days tending her Victory Garden, listening to soap operas, and worrying about her son Jimmy. She firmly believes in the moral righteousness of the war and prefers not to interfere in other families' private matters, maintaining a strict policy of minding her own business.

Mr. Baker is the family breadwinner. Since his son Jimmy shipped out to war, he has become distant, serious, and short-tempered, losing the cheerful demeanor Margaret once loved. He is entirely consumed by radio and newspaper updates about the conflict overseas.

Mrs. Smith is the timid, submissive mother of the Smith children. Terrified of her violent husband, she attempts to hide the reality of her family's abuse from the outside world. She explains away her injuries as clumsiness and aggressively rejects offers of intervention from concerned neighbors out of fear.

Donald is the eldest Smith brother, known in College Hill as a former bully and hooligan who used to blow up gas stations and damage trolley cars. Now a soldier serving in the war, his letters reveal a grim, cynical perspective on combat that shatters the patriotic illusions of those back home.

June is Gordy's little sister, a vulnerable child who suffers under her father's violent temper. She relies heavily on Gordy, who acts as her primary comforter and protector when the house becomes unsafe.

Mrs. Wagner is a formidable, unsmiling teacher known for her strict discipline and heavy homework loads. She enforces a strict "no tattling" policy in her classroom and keeps a sharp eye on students she suspects might cause trouble.

Joe is Elizabeth's older brother, currently fighting in the war. His military service fuels Elizabeth's intense patriotism and her initial disgust toward anyone who avoids their duty to the country.

Toad is one of Gordy's two loyal followers. He participates in Gordy's commando war games, helps tear up the girls' treehouse, and assists in maintaining the secrecy of the hidden hut in the woods.

Doug is one of Gordy's constant companions. Alongside Toad, he acts as Gordy's backup during confrontations with the girls and spends his free time smoking cigarettes and reading comics at the secret woodland hut.

Butch was a star high school quarterback who married Barbara shortly before shipping out to war. He was killed in action before ever meeting his son, leaving behind a grieving young widow and a collection of military medals.

Brent is Barbara and Butch's infant son. He represents the innocent next generation, serving as the primary reason his mother fiercely opposes the destructive nature of the war.