Lucy is a 12-year-old American-born child of Chinese immigrants. She and her younger sibling live in deep poverty in the California goldfields, where their Asian features mark them as permanent outsiders to the local townsfolk. Despite enduring physical and emotional abuse from her father, she feels fiercely duty-bound to give him a traditional burial. She desperately longs for civilization, education, and a permanent place to call home.

Sam is Lucy's 11-year-old sibling. Though assigned female at birth, Sam adopts a male identity early on, cutting his hair and dressing as a boy to gain more freedom and appease their father. He possesses a confident, stubborn charisma that Lucy admires. Sam inherits his father's obsession with the untamed hills and dreams of striking it rich as a gold prospector.

Ba is the deceased father of Lucy and Sam. An unsuccessful gold prospector, he dragged his family from one California settlement to another in a relentless pursuit of sudden wealth. Though he appears Chinese to the locals, he is a native-born American with a complicated, obscured past. His grief and consistent failures turn him toward alcohol, making him harsh and unpredictable toward Lucy while doting heavily on Sam.

Ma is the native-born Chinese mother of Lucy and Sam. To her children, she is remembered as a stabilizing force who painted protective tiger talismans on the dirt floors of their makeshift shacks. She outwardly appears to be a placid, self-sacrificing wife who endures her husband's endless schemes, though she hides a sharp intelligence and deep ambition of her own.

Mr. Leigh is a schoolteacher and self-proclaimed historian living in the goldfields. He values order and civilization, taking an immediate interest in Lucy because of her intelligence and eagerness to learn. He serves as Lucy's brief connection to formal education and the broader world of historical records, though his views are heavily prejudiced by the standards of his time.

Anna is the privileged daughter of a wealthy gold prospector living in Sweetwater. From behind, she shares a striking physical resemblance to Lucy, representing the comfortable life Lucy might have lived if her own father had struck gold. She treats Lucy with casual generosity, offering cast-off clothing and food, but views her more as a harmless domestic pet than an equal.

Charles is Anna's wealthy fiancé. He enjoys the comforts and social standing that come with his engagement to a rich prospector's daughter, but he entertains himself by aggressively flirting with Lucy behind Anna's back.

Elske is the madame of a brothel in San Francisco. She runs a highly stylized business where the workers dress as characters from fantasy storybooks and pose in frames. She is shrewd, business-minded, and quick to recognize desperation in the people who walk through her doors.

The Gold Man is a dangerous, physically imposing figure operating in San Francisco. He violently pursues Sam over a dispute regarding stolen gold, using lethal threats and extortion to enforce his will and reclaim his wealth.

The Mountain Man is a solitary traveler who encounters the orphaned siblings during their bleak journey. He freely shares his food with them and entertains Sam with wild stories about surviving in the untamed hills.