Candice is a twelve-year-old Black girl spending her summer in Lambert, South Carolina, following her parents' recent separation. Intelligent, observant, and an avid reader, she discovers a mysterious letter inside a puzzle book in her grandmother's former attic. She is determined to solve the historical clues to clear her late grandmother's disgraced reputation, showing deep loyalty and sharp analytical skills.

Brandon is an eleven-year-old Black boy living across the street from Candice's summer house. Quiet, highly intelligent, and an avid reader, he faces bullying from local boys who perceive him as different. He becomes Candice's dedicated research partner, bringing strong logic skills and local knowledge to their investigation of the town's history.

A prominent figure in 1950s Lambert, serving as a teacher and athletic coach at Perkins High, the local all-Black school. Known as Big Dub, he is a proud, educated man who actively resists the era's deep-seated segregation. He organizes a fateful, highly contested private tennis match between his students and the local all-white school.

Coach Washington's daughter is a highly intelligent high school student in 1957 Lambert who works at an after-school tutoring service. She loves literature, poetry, and riddles. The historical mistreatment of her family serves as the central catalyst for the modern-day mystery Candice investigates.

A bright, athletic Black teenager in 1950s Lambert who lives with his grandmother in poverty. He has gray eyes and light skin, and faces significant social challenges from his peers. Despite his coach's disapproval, he is a dedicated reader who trades poetry and intellectual challenges with Siobhan Washington.

Candice's mother is a romance novelist currently fighting writer's block and tight deadlines. She brings her daughter to Lambert to organize her late mother's house while managing the stress of a recent separation and tight finances. She is fiercely supportive of Candice despite her own heavy burdens.

Candice's father is a contractor who remains in Atlanta to renovate the family home for sale. He is a caring parent who shares a special bond with Candice through music, particularly classic R&B. His physical distance and evasiveness about the reasons behind the marital separation create an emotional barrier between him and his daughter.

Candice's late grandmother was a former Lambert city clerk. Ten years prior to the main story, she discovered a mysterious letter promising a massive inheritance to the city and was fired after her destructive attempt to unearth it. She is remembered as a kind, intelligent woman who nurtured Candice's early love for logic games.

Brandon's older sister is a stylish and responsible teenager who works at a local retail store. She is highly protective of her brother against local bullies and serves as a supportive older figure for both him and Candice, often providing rides for their historical research.

Brandon and Tori's mother is a welcoming neighbor who quickly befriends Anne Miller. She is a caring parent who worries about Brandon's emotional outbursts and social isolation during the summer break, trying to facilitate positive friendships for him.

An AP History teacher and the dedicated curator of the Perkins Memorial Room at the local high school. She is enthusiastic about Lambert's history and eager to help Candice and Brandon unearth archival documents, yearbooks, and photographs related to the 1950s.

A local boy in Lambert who frequently targets and bullies Brandon. He uses homophobic slurs and physical intimidation to assert dominance, creating a persistent source of anxiety for Brandon throughout the summer break.

Brandon's grandfather is an older resident of Lambert who holds traditional views about masculinity. He provides Candice and Brandon with initial oral history about the town's segregated past, though he frequently clashes with Brandon over his interests.

Milo's mother and a member of the local Lambert church. She is nosy, abrasive, and frequently pries into the Miller family's personal business, particularly regarding their financial status and Anne's recent separation.

Coach Washington's wife and Siobhan's mother in 1950s Lambert. She is an intelligent, politically active woman deeply involved in raising money to fight segregation, often acting as a voice of caution and foresight for her impulsive husband.

The white teenage son of the athletic director at the all-white high school in 1950s Lambert. He harbors a persistent crush on Siobhan Washington, constantly seeking her out despite her clear rejections, and struggles to understand the deep racial divides that separate them.

The athletic director at Wallace, the all-white high school in 1950s Lambert. He maintains a pragmatic, somewhat cautious relationship with his Black counterpart, Coach Washington. He understands the dangerous racial realities of the town far better than his son does.

An assistant principal at Perkins High School. He immediately assumes the worst of Candice and Brandon when he finds them outside the building, accusing them of lying and demanding identification in a hostile, racially motivated encounter.

A former classmate and friend of Siobhan Washington from the 1950s. Now an older woman, she warmly welcomes Candice and Brandon into her home to provide vital firsthand information about Siobhan's academic brilliance and the origins of Candice's bracelet.

Brandon's best friend who typically plays basketball with him and provides steady companionship. His absence during the summer vacation leaves Brandon feeling isolated and more vulnerable to local bullies until Candice arrives.

The oldest son of the powerful, wealthy white Allen family in 1950s Lambert. He is violently racist and orchestrates the aggressive retaliation against the Black community following the high school tennis match, forcing the Washington family to flee.

A white tennis player for Wallace High School in 1957. He plays against Reginald Bradley during the fated exhibition match, initially believing he is winning before Reginald reveals his true skill level on the court.

An adult present during the 1957 exhibition tennis match. He attempts to protect Siobhan Washington when the post-game argument between the coaches turns violent, trying to escort her away from the escalating danger.

A deacon at the local church Milo and Brandon attend. He is an older community member who personally remembers Coach Washington and provides the children with old photographs and historical documents to aid their investigation.