Characters in The Traitor in the Tunnel

Mary Quinn

A quickwitted agent for the Agency, she poses as a domestic in Buckingham Palace to investigate a thief and later a murder, while also confronting a personal connection to the accused killer.

Also in A spy in the house, The body at the tower

James Easton

An engineer working on the sewers beneath Buckingham Palace, he is Mary's onetime paramour and becomes involved in the mystery of an unexpected tunnel.

Also in A spy in the house, The body at the tower, Rivals in the City

Prince of Wales

A feckless prince whose attentions Mary must fend off, and who witnesses a murder in an opium den, creating a potential scandal.

Mary Lang

Also in A spy in the house, The body at the tower, Rivals in the City

Felicity Frame

Also in A spy in the house, The body at the tower

Anne Treleaven

Also in A spy in the house, The body at the tower