Times are turbulent in 1880s London with social unrest rife across the city. Scotland Yard have their eye on many potentially disruptive gangs and political groups and Eliza is hired by Duke to go undercover and infiltrate one such organisation.
Eliza is delighted - this is progress and a show of faith in her abilities. However, she is less pleased when she learns who she will be spying on - a women's suffrage group campaigning for the vote. Eliza is conflicted, is she a woman or a detective first?
As London's first female detective, Eliza knows a thing or two about empowerment, but she also knows right from wrong and there's more than a whiff of danger when she befriends a strong-willed suffragette who is prepared to do anything to further her cause.