Eliza is a young woman of obscure origins raised in the English colony of Valparaíso. She possesses an extraordinary sense of smell and a superb memory. Caught between the strict, European upbringing of her adoptive aunt and the indigenous traditions of the household cook, she develops a rebellious streak. Her intense first love for a local shipping clerk prompts her to secretly travel to California during the Gold Rush.

Rose is an English spinster living with her brother Jeremy in Chile. She outwardly embodies the conventions of a Victorian lady but privately harbors a passionate history and writes erotic fiction in secret notebooks. She desires to mold Eliza into an accomplished woman capable of securing a comfortable marriage, hoping to spare the girl the restrictions she herself faces.

Tao is a skilled traditional Chinese physician (zhong yi) who was forced to leave his home after a series of tragedies. Initially known as Fourth Son, he survived poverty and indentured servitude through his medical talent. He is observant, compassionate, and spiritually connected to his deceased wife, eventually becoming Eliza's closest ally in California.

Mama Fresia is the stout Mapuche Indian cook in the Sommers household. She serves as Eliza's second mother, offering a warm, nature-based alternative to Rose's strict English rules. She teaches Eliza how to cook, speaks to her in a mix of Spanish and Mapuche, and utilizes ancient herbal remedies.

Jeremy is the self-controlled, emotionally distant patriarch of the Sommers family. As the director of the British Import and Export Company, he represents the rigid social and patriarchal order of the 19th-century English colony in Chile. He values appearances and propriety above all else, often dismissing the emotional needs of those around him.

John is a hard-drinking, affable sea captain who frequently visits his siblings in Valparaíso. He provides a sharp contrast to his pale, rigid brother Jeremy with his tanned, healthy, and open demeanor. He brings an air of adventure to the Sommers household and secretly deposits money from Rose's writings into a London bank account.

Jacob is an eccentric, charismatic Englishman who travels to Chile under the guise of being a missionary. He quickly assimilates into the upper-class social circles but nurses an unrequited love for Miss Rose. Following a scandal, he eventually relocates during the California Gold Rush and adopts an Americanized persona as a journalist.

Joaquín is a charismatic, impoverished shipping clerk working for Jeremy Sommers. Born out of wedlock, he carries the stigma of his birth while burning with revolutionary zeal and a desire to help the working class. He views the California Gold Rush as his only chance to escape poverty and become worthy of asking for Eliza's hand in marriage.

Paulina is the intelligent, rebellious daughter of a wealthy, traditional Chilean family. She rejects the submissive role expected of women in her society, choosing instead to marry for love and pursue ambitious business ventures. Her sharp intuition eventually leads her to build a highly profitable shipping enterprise during the Gold Rush.

Feliciano is a newly rich Chilean entrepreneur who makes his fortune through mining. Despite the old aristocracy's disdain for his background, he successfully marries Paulina del Valle. He is an unusually progressive husband for his era, actively encouraging his wife's business ideas and sharing the resulting profits.

Karl is a Viennese opera singer who crossed paths with Miss Rose when she was a sixteen-year-old girl. Though he lacks physical beauty, his powerful voice and experienced charm lead to a brief but intensely passionate affair that alters the course of Rose's life.

The master is a respected traditional Chinese physician who takes Tao on as an apprentice. He teaches the young man the arts of acupuncture, herbal medicine, and calligraphy. His despair over the Opium War's outcome leads him to a tragic end, though his teachings profoundly shape Tao's future.

Dr. Hobbs is a young, aristocratic English physician who lacks the typical prejudice of his peers. He recognizes the value in Eastern medical practices and forms a rare, mutually respectful friendship with Tao, trading knowledge about surgery and acupuncture.

Lin is Tao's Chinese wife, purchased through an agent. Despite Tao's low expectations for an arranged marriage, Lin reveals herself to be a complex, humorous, and intelligent companion. Her health is severely compromised by the traditional practice of foot-binding.

Azucena is a Chilean prostitute with indigenous ancestry who travels to California hoping to secure her financial independence. She is hired by Tao to secretly nurse the gravely ill Eliza during the sea voyage, offering the younger woman maternal care and discretion.

Joe is a Pennsylvania Dutch woman who runs an itinerant brothel in the California mining camps. Wearing men's clothing and possessing a tough exterior, she provides a surprisingly safe and maternal environment for the women in her employ. She hires Eliza to play the piano for her establishment.

Ah Toy is a historical figure depicted as a clever and ruthless madam in Gold Rush-era San Francisco. She builds a criminal empire by importing young Chinese girls and forcing them into prostitution, actively profiting from the vulnerability of her own people.

James is a robust Quaker blacksmith with a history of helping fugitive slaves in Ohio. He stands out in the rough mining camps for his moral compass, eventually assisting Joe Bonecrusher during an epidemic and connecting rescued women to abolitionist networks.

Agustín is the wealthy, traditional patriarch of the del Valle family, descended from Spanish conquistadors. He rules his household with an iron fist, granting freedom to his sons while demanding absolute submission from his wife and daughters.

Babalu the Bad is a physically massive man who serves as the bodyguard for Joe Bonecrusher's traveling brothel. Despite his intimidating appearance, he shows genuine camaraderie toward the workers and bravely rescues members of the household during a fire.

Esther is a young woman who turned to sex work as a means to escape severe physical abuse from her father. Under Joe Bonecrusher's maternal management, she finds temporary safety before eventually leaving the profession to marry.