Lavender Reed, Bow Street Runner and his daughter, Calista, you may have met in my earlier book,  Murder Most Foul (2021).   Cally, as she is known, is Anglo-Indian.​   ​ The present story is set in the first half of the 19th century, during the Napoleonic wars and the Regency period.​ Cally and her adoptive sister, Polly, rebel against almost every rule in the book.​ At a time when most young women of their class are housebound, decorous and docile, the sisters are activists in the causes of prison reform, the abolition of slavery and the long campaign for universal suffrage.  In 1820, they are party to the Cato Street conspiracy. They attend Quaker meetings, although atheist. ​Their dress is often unorthodox, including breeches when always riding astraddle, never side-saddle.​ They make no secret of their love for each other, when sapphic love is unknown or unmentionable.​ They share the mothering of an adopted black orphan girl, whose mother was a slave from Benin.​