Evangeline is a 21-year-old governess, the educated but naive daughter of a country vicar. Employed by the wealthy Whitstone family in London, her quiet life shatters when she becomes pregnant by the family's eldest son and is subsequently accused of theft. Sentenced to fourteen years in an Australian penal colony, she boards the transport ship Medea, where she must use her inner strength to adapt to a brutal new reality.

Hazel is a sixteen-year-old Scottish girl sentenced to transport for stealing. Raised by a disgraced prominent midwife, she possesses extensive practical knowledge of herbal remedies and healing. Despite her youth and the harshness of her circumstances, she is resourceful, street-smart, and deeply loyal to the few people who show her genuine kindness.

Mathinna is an eight-year-old Palawa girl, the orphaned daughter of a tribal chieftain. She is forcibly taken from her people to live with the British governor's family in Van Diemen's Land. Required to wear restrictive British clothing, learn French, and entertain high-society guests, she tries to maintain her cultural identity while forced into a world that views her as an exotic curiosity.

Ruby is the child of Evangeline Stokes and Cecil Whitstone, born during the harsh sea journey to Australia. Her existence serves as a central anchor for the women on the Medea, prompting them to band together to ensure her survival in the penal colony. She represents the hope of a new generation unburdened by the rigid social hierarchies of Victorian England.

Doctor Dunne is the young ship's surgeon aboard the Medea. Seeking to escape the ruin of his family's medical reputation in London, he takes the post on the convict transport with hopes of eventually establishing a private practice in Australia. He treats the convict women with a level of dignity and respect rarely found among the rest of the crew.

Cecil is the charming, wealthy eldest son of the Whitstone family. He pursues an affair with the family governess, Evangeline, giving her a valuable family ruby ring and assuring her that societal rules do not matter to him. When Evangeline is accused of theft, he is conveniently absent on vacation, completely insulated from the devastating consequences of his actions.

Lady Jane is the ambitious, shrewd wife of the Governor of Van Diemen's Land. Viewing native culture as a curiosity, she treats Mathinna as an exotic pet project. She forcefully strips the girl of her heritage to display her successful civilizing experiment to her high-society peers, collecting native skulls and artifacts for her personal curio room.

Danny Buck is a cruel, unruly sailor on the Medea who previously completed his own sentence at the penal colony. He uses his position of power on the ship to harass and terrorize the female convicts. He holds a deep grudge against Evangeline and Hazel after they thwart his violent advances, dedicating himself to seeking vengeance.

Olive is a boisterous, blond-haired sex worker in her thirties who is incarcerated alongside Evangeline. Sentenced to transport for killing a man who refused to pay her, she is rough around the edges and heavily pregnant. She provides blunt, practical advice to her fellow convicts and uses her sharp wit to fend off unwanted attention from the sailors on the transport ship.

Maeve is an older Irish midwife sentenced to seven years of labor after cursing her landlord. Outspoken and highly knowledgeable, she meets Hazel at the penal facility in Hobart Town. She becomes a maternal figure and a vital source of education, teaching Hazel the medicinal and dangerous properties of native Australian flora.

Sir John is the Governor of Van Diemen's Land, a man who relies heavily on his wife's ambition to maintain his political standing. While he is generally more amiable toward Mathinna than his wife is, taking walks with her and teaching her plant names, he remains passive and prioritizes his political safety over intervening in his wife's cruel experiments.

Eleanor is Sir John Franklin's daughter from a previous marriage. Unlike her stepmother, she approaches Mathinna with a practical mindset, taking on the role of teaching the girl French, mathematics, and proper English dancing. She views her stepmother's ambitions with amused apathy and remains generally detached from the household's emotional dramas.

Mrs. Whitstone is the wealthy matriarch of the London household where Evangeline works. When a valuable family heirloom is discovered in Evangeline's room, Mrs. Whitstone immediately assumes the worst, refusing to believe her son would willingly gift it to a governess, and promptly hands Evangeline over to the authorities.

Agnes is a servant in the Whitstone household. She discovers Evangeline's morning sickness and the ruby ring, quickly realizing that the young governess has compromised herself. Her mocking attitude pushes Evangeline into a momentary panic that escalates into severe criminal charges.

Palle is Mathinna's stepfather and a member of the Palawa tribe. He provides Mathinna with the oral history of their people and the devastating impact of British colonization before she is forced to leave for Hobart Town.

Towterer was the chief of the Lowreenne tribe and Mathinna's biological father. Though he died of tuberculosis when she was young, his legacy leaves Mathinna viewed as tribal royalty among her people.

Waluka is Mathinna's pet possum, raised from a baby. As one of the few things she is allowed to bring from Flinders Island, the animal serves as Mathinna's last living connection to her homeland and her true identity.

Mrs. Crain is the strict housekeeper at the Franklins' residence. She manages the convict maids and oversees the daily operations of the estate, viewing Mathinna primarily as a dirty nuisance who must be scrubbed and managed to meet British standards.

Mrs. Wilson is the cook at Government House. A former convict herself, she grumbles freely about her wealthy employers but occasionally shows a softer side, particularly when she and Mathinna work together to extinguish a small kitchen fire.

John Montagu is the Colonial Secretary who frequently visits Sir John Franklin to engage in political intimidation tactics. He represents the ruthless political machinery of the British colonial government.

Mr. Hutchinson is the strict superintendent of the penal facility in Hobart Town. He enforces harsh routines and severe punishments, maintaining absolute control over the female convicts in his care.

Mrs. Fry is a compassionate Quaker woman who visits the female prisoners at Newgate and the Medea. Unlike the condemnatory preachers, she offers the women practical help, clean clothing, and a message of inherent human worth and redemption.

Sarah is a young housemaid at the Franklin estate. As a well-behaved convict allowed to work in a free settler's home, she helps integrate Mathinna into the household routines, dressing the girl in Eleanor's old clothes.

George Robinson is the Englishman in charge of Flinders Island. He operates under the belief that civilizing the native population requires feeding their souls with Christianity so they forget their cultural ways, completely missing the damage caused by the British occupation.