Jean secures a position as a governess for the wealthy Coventry family by posing as a meek, teenage Scottish orphan. She is in truth a thirty-year-old former actress who relies on false hair, cosmetics, and a fake accent to maintain her youthful disguise. Driven by her precarious economic standing in Victorian society, she uses her theatrical skills to manipulate her employers. She carefully adjusts her personality to please each member of the household, aiming to secure a comfortable and permanent future.

Gerald is the elder son and de facto master of the Coventry estate. Raised without challenges, he suffers from a profound indolence and approaches life with detached cynicism. He spends his days lounging around his home, neglecting his duties as the head of the family and failing to secure a military commission for his younger brother. He initially views his new employee with classist disdain and amusement, confident he can see through her modest presentation.

Sir John is the wealthy, older uncle of the Coventry siblings, living alone at the neighboring Hall. He visits his relatives frequently to enjoy the energy of a bustling household. He prides himself on his gentlemanly conduct and holds deep respect for aristocratic lineage. He remains unaware that his loneliness makes him highly susceptible to flattery, particularly from young women who ask for his guidance.

Edward is Gerald's younger, more energetic brother. He possesses a surplus of energy that he cannot direct, as he waits endlessly for his older brother to finalize his military commission. He approaches life with a boyish sincerity, showing immediate kindness to the new arrival when his brother shows only disdain. His open, romantic nature makes him quick to fall in love.

Lucia is a proud, wealthy cousin of the Coventry family who resides with them. She represents the traditional Victorian ideal of a proper woman and expects to marry Gerald, though they remain only informally betrothed. She strictly enforces class boundaries and watches the new governess with intense suspicion, correctly sensing a disruption to the household's social order.

Isabella, frequently called Bella, is the sixteen-year-old sister of Gerald and Edward. As the family's youngest member, her education is the sole reason for a governess's presence in the house. She readily accepts her new teacher as a friend and confidante, sharing family gossip without realizing the strategic value of her chatter.

Mrs. Coventry is the frail, nervous matriarch of the family. She rarely exerts authority over her home, preferring to rest on the sofa and manage her delicate nerves. She dreads any disruption to her quiet routine and eagerly hands over household responsibilities to anyone willing to brew a proper cup of tea and speak in soothing tones.

Hester serves as Lucia Beaufort's personal maid, navigating the household with the practical wisdom of the working class. She shares her mistress's disdain for the new governess and uses her invisibility as a servant to observe hallway conversations, misplaced letters, and covert interactions.