Kitty is a beautiful, socially conscious 25-year-old woman who marries hastily to avoid the embarrassment of remaining single. Raised by an ambitious mother, she values charm and social standing over deeper virtues. Living in colonial Hong Kong, she feels disconnected from her quiet husband and seeks excitement elsewhere.

Walter is an intelligent but socially awkward bacteriologist stationed in Hong Kong. He possesses strong facial features but lacks the outgoing charm valued by colonial society. He loves his wife deeply, fully aware of her shallow nature, but struggles to express his feelings openly.

Charles is the Assistant Colonial Secretary in Hong Kong, standing six-foot-two with a fashionable, athletic presence. He is highly popular and charming. He prioritizes his career advancement and public image above all else. He enjoys the thrill of extramarital affairs but relies heavily on his wife for social stability.

Dorothy is the well-connected wife of the Assistant Colonial Secretary and the daughter of a former governor. She has pale brown hair, unremarkable features, and a cold but composed demeanor. She acts as the social arbiter of the British colony and quietly manages her husband's public image.

Mrs. Garstin is a harsh, ambitious woman who moved from industrial Liverpool to London to advance her social standing. She prioritizes status above her family's happiness. She pushes her husband into unsuitable jobs and treats her daughters as investments on the marriage market.

Bernard Garstin is a subdued, hardworking man who provides for his family while remaining emotionally distant. He lacks the ruthless ambition his wife demands. He finds himself trapped in stressful positions to fund her social gatherings.

Doris is Kitty's younger sister, described as having a lumpy figure and an awkward dancing style. Despite these traits, she secures an engagement to a wealthy baronet during her first social season. Her sudden success completely disrupts the family's expectations.

Waddington is a bald, thin deputy commissioner living in the remote outpost of Meitan-fu. He drinks heavily but observes the world with sharp clarity and brutal honesty. Unlike many colonists, he holds a genuine, cynical appreciation for Chinese culture.

The Mother Superior is a middle-aged French noblewoman who left behind a life of privilege to run an orphanage and hospital in China. She possesses an aura of total authenticity. She commands respect through her calm dedication to her charitable duties.

Sister St. Joseph is a plump, red-cheeked French nun who grew up on a Breton farm. She maintains a lively, down-to-earth demeanor. She enjoys a bit of harmless gossip while working tirelessly among the sick and orphaned.

The Manchu Princess is a member of the fallen Chinese nobility who lost her standing during the revolution. She wears elaborate traditional dress and heavy makeup. She lives a quiet, isolated life as the devoted companion to a British official.

Colonel Yü is a Chinese military officer enforcing harsh but necessary quarantine rules in Meitan-fu. He works closely with the medical staff to ensure the dead are buried quickly. He shows a stern dedication to stopping the epidemic.