Rob is a quiet, polite 12-year-old boy who has recently moved to Lister, Florida, with his father. Still deeply grieving his mother's recent death from cancer, Rob mentally locks his sad memories and feelings away in an imaginary suitcase. His repressed emotions manifest physically as a severe, itchy rash on his legs. He is a talented whittler, a skill his mother taught him, and he actively avoids social interaction at school to keep his emotional barriers intact.

Sistine is a fierce, outspoken girl who recently moved to Lister from Philadelphia after her parents separated. She is highly intelligent, appreciates art, and frequently gets into physical fights at school to express her anger and frustration. She stubbornly believes her father will come to rescue her from her new life in the South, which she loudly despises.

Robert is Rob's grieving father, a hardworking maintenance man at the run-down Kentucky Star Motel. Following the death of his wife, Caroline, he suppresses his sorrow entirely, forcing himself and his son to bury their memories. He is gruff and practical but deeply loves his son, secretly sacrificing his own meager meals so Rob can eat more.

Beauchamp is the swaggering, immature owner of the Kentucky Star Motel and the surrounding woods. He flaunts his supposed wealth with gold chains, though he underpays his employees and relies heavily on his mother. Cowardly despite his boastful exterior, he acquires a wild animal as payment for a debt but is secretly terrified to care for it himself.

Willie May is the tall, observant housekeeper at the Kentucky Star Motel. With a smooth face and a comforting smell of licorice gum and cigarette smoke, she serves as a wise, grounding presence for both Rob and Sistine. She quickly perceives that Rob's physical ailments are tied to his unexpressed sadness and challenges both children to face their emotional truths directly.

Caroline is Rob's deceased mother, whose recent death from cancer hangs heavily over her fractured family. She was a gentle, artistic peacemaker who taught Rob how to whittle wood and brought warmth into their home. Her absence creates a profound void that drives the emotional isolation of both her husband and son.

A magnificent, fierce wild creature kept locked in a small cage in the Florida scrub. The animal paces restlessly, serving as a powerful, beautiful secret for Rob and a focal point for Sistine's intense sense of justice and anger about captivity.

Mr. Phelmer is the principal of the local school in Lister. Concerned about complaints from other parents, he assumes Rob's emotional rash is a contagious disease and suggests the boy stay home, inadvertently giving Rob exactly the isolation he wants.

Norton is a loud, aggressive bully who rides the school bus with Rob. Along with his brother, he relentlessly mocks Rob's physical appearance, particularly his rash, taking advantage of the quiet boy's passive nature.

Billy is the other half of the local bullying duo. He participates enthusiastically in punching and verbally harassing Rob, testing the boy's strict personal policy of enduring abuse in total silence.

Sistine's mother recently relocated herself and her daughter to Lister following her husband's infidelity. She is sharp-featured and impatient, attempting to force her daughter to conform to Southern culture while dealing with Sistine's fierce and vocal rebellion.

Sistine's father remains in Pennsylvania after having an affair with his secretary. Though physically absent from the story, he is fiercely idealized by his daughter, who uses the fantasy of his return as a shield against her current unhappy reality.