An aristocrat with progressive views, Lady Rowan is a benefactor and supporter of Maisie, providing her opportunities for education and professional growth. She represents a link to Maisie's past as a servant in her household.

A close family friend of Lady Rowan, Maurice is an accomplished investigator and acts as a mentor to Maisie, encouraging her intellectual and emotional development. He has a broad understanding of human motivation and crime.

Maisie's father, a kind and devoted man who sacrifices his own dreams to provide for his daughter. His support and love remain a constant source of security for Maisie.

A housemaid in the Compton household and Maisie's former roommate, Enid initially mentors Maisie while harboring her own ambitions and secret romance with the noble James Compton.

Caretaker at Maisie's office building, Billy is a war veteran who respects Maisie for her past assistance as a nurse and helps her with investigative work. He provides valuable insight into the farm known as the Retreat.

Maisie's sociable and extroverted roommate from Cambridge University, Priscilla becomes her friend and influences Maisie's social and romantic developments.

Maisie's first love, a surgeon she meets through Priscilla, whose relationship with Maisie explores themes of love and sacrifice amidst the realities of war.

Christopher is Maisie's wealthy client who suspects his wife, Celia, of infidelity. The investigation into their relationship highlights Maisie's empathetic and methodical approach to her work.

Leader of the Retreat, a farm for injured soldiers, Jenkins becomes a key figure in Maisie's investigation into mysterious deaths, reflecting the story's themes of war and its consequences on individuals.