Maya is an 11-year-old girl living a highly constrained life with her paternal grandmother after the deaths of her parents. Having endured years of emotional suppression and secrecy, she resorts to telling elaborate lies as a primary coping mechanism. When sudden circumstances force her relocation to a family camp in Wyoming, she must confront her deepest fears. There, she learns to connect with her maternal relatives and the natural world, actively shedding the psychological restrictions of her past.

Artemisia is a wild, confident Paint mare who serves as the lead mare of her band. Named after an artist by those who admire her from afar, she relies on her deep knowledge of the terrain to keep her herd safe. Her instincts for survival contrast sharply with the domesticated constraints of Maya's early life.

Aunt Vi is a former art history professor who runs a wilderness camp along the Sweetwater River. Energetic and demanding, she does not tolerate dishonesty and actively pushes those around her to face their fears. She maintains a deep respect for the land and wild horses, blending practical survival skills with emotional openness.

Agnes Menetti is Maya's 88-year-old paternal grandmother, residing in an obsessively pristine, plastic-covered home in Pasadena. Consumed by bitter grief over the death of her son, she attempts to erase all traces of Maya's mother from their lives. Her strict rules and emotional coldness force Maya to hide her true feelings and maternal connections.

Payton is Maya's 10-year-old cousin who spends his summers at Aunt Vi's camp. Feeling displaced by Maya's sudden arrival, he initially acts out through territorial pranks and hostility. He excels at horseback riding, which offers him a sense of accomplishment away from his older brothers at home.

Walter 'Moose' Limner is Maya's burly, cowboy-hat-wearing maternal grandfather. Unlike the emotionally guarded environment Maya is used to, Moose wears his heart on his sleeve and openly weeps at memories of his late daughter. He offers Maya an immediate source of warm, unconditional affection.

Frederick 'Fig' Limner is Maya's tall, thin great-uncle who helps run the family ranch. He acts as the camp's self-proclaimed cook and provides a steady stream of trivia about the Wyoming territory. His good-natured teasing and gentle demeanor help ease Maya's transition into the family.

Klee is a newborn brown-and-white tobiano colt in the wild horse band. Playful and energetic, he quickly learns the social rules of the herd while staying close to his mother for protection.

Ellie is Maya's late mother, who died in a car accident six years before the events of the story. Remembered for her joyful spirit and deep love of horses, her legacy is fiercely protected by her Wyoming family and secretly cherished by Maya.

Sargent is a palomino stallion and the protective leader of his wild horse band. He actively patrols his territory, guards against predators, and enforces the strict social hierarchy among the herd's members.

Morgana is one of the many housekeepers employed by Grandmother Menetti. Well-paid and determined to enforce the household's strict rules, she quickly becomes a target for Maya's acts of sabotage after discovering the girl's hidden toy horses.

Seltzer is a dependable blue roan horse assigned to Maya for her riding lessons. His intense physical presence forces Maya to confront her fears of horseback riding.

Wilson is a sorrel horse primarily ridden by Payton. He is known for constantly trying to escape his enclosure, requiring careful attention to the latches on his gate.

Mr. Benedetto is Grandmother Menetti's lawyer. Following a household medical emergency, he is responsible for informing Maya about the hidden truths in her parents' will and orchestrating her relocation to Wyoming.

Gregory is Maya's late father. Raised by a highly controlling mother, he met Ellie during a painting trip in Wyoming before dying alongside her in a tragic car accident.