Sallie is a bookish and reflective young woman living on the Yates family plantation in the 1840s. Following a past incident that severely damaged her social standing, she expects a quiet and constrained life. When the wealthy Bunker twins express interest in courting the sisters, Sallie is deeply hesitant about the unusual arrangement. She spends her free time reading literature, which shapes her evolving worldview.

Addie is Sallie's bold, beautiful, and ambitious younger sister. Frustrated by the limitations of rural life and her diminished marriage prospects, she views the arrival of the wealthy Bunker twins as a strategic opportunity. She is pragmatic and persuasive, often using her strong will to direct her sister's choices toward a more advantageous future.

Eng is one of the world-famous conjoined twins from Siam, newly settled in North Carolina to establish a plantation. He is reserved, sensitive, and intellectual, preferring literature and quiet conversation over public performance. He seeks a wife to build a respectable family life and secure his permanent status in Southern society.

Chang is the more outspoken and charismatic of the conjoined Bunker twins. Having spent years on the exhibition circuit, he is skilled at managing public attention and uses his wit to charm society. He is highly ambitious, determined to secure wealth, land, and a beautiful wife to prove he has transcended his past as an exploited performer.

Grace is an intelligent and guarded enslaved woman working in the Yates home. Once a childhood playmate of Sallie's, she was forced into servitude and forbidden from learning to read. This creates a formal, distant dynamic between the two young women as they grow older.

Aunt Joan is the fiercely independent and unconventional sister of David Yates. She lives alone, refuses to conform to traditional Southern society, and openly condemns the institution of slavery. She provides a safe haven, practical work, and moral mentorship to her niece.

David is a wealthy plantation owner and the patriarch of the Yates family. He presents himself as a principled Quaker but actively enslaves people. He is deeply concerned with social propriety and public reputation, acting as a strict authority figure over his daughters' controversial courtship with the twins.

Mrs. Yates is Sallie and Addie's mother, a reclusive and emotionally distant woman who largely confines herself to the house. Her withdrawal from society stems from a traumatic event in her youth, leaving her daughters to conduct their courtships without maternal guidance.

Tom Fellows is a charming traveling salesman whose visit to the Yates farm results in a major scandal for Sallie. He uses his charisma to gain the family's trust before taking advantage of a young woman's innocence while her father is distracted.

Charles is a local man and acquaintance of the Yates family. As a former manager for Chang and Eng Bunker, he introduces the wealthy brothers to local society and facilitates their first meeting with the Yates sisters.

Alston is the son in the Yates family, growing up on the family plantation. His position as the male heir provides him with a secure place in Southern society, contrasting sharply with his sisters' restricted prospects.

Dinah is an enslaved woman on the Yates family plantation who has spent her entire life working for the family. She is the mother of Grace and lives under the constant threat of family separation inherent to the antebellum economy.

Abel Coffin is a ship captain and the former manager of Chang and Eng Bunker. He brought the brothers from Siam to the United States, controlling their finances and travel while heavily profiting from their public exhibitions before they gained independence.

Phoebe is an enslaved woman leased by the Bunker brothers to work on their new estate. She possesses extensive traditional knowledge as a midwife and healer, assisting the women of the household with herbal remedies and domestic duties.

Cato is an enslaved blacksmith leased by the Bunkers to help establish and maintain their new, expanding farm in North Carolina. He provides vital labor for the brothers' agricultural ambitions.