A valuable sketch by the late Charles Darwin has been stolen and Eliza is hired by an insurance company to find it, but a twist soon emerges.

Eliza is forced into hiding when she is the prime suspect in a series of break-ins at city mortuaries. While Duke tries to find other suspects, Eliza turns to Moses for help.

Eliza is hired to solve a case of blackmail in the shady world of Victorian medicine, and finds herself with a new rival-Patrick Nash, the owner of a large private detective agency who wants to hire her or crush her agency.

A famous mystery writer is at the centre of Eliza's investigation when a series of murders copy scenes in his books. Meanwhile, the Duke is also juggling problems at work with a new superintendent and a troubled young detective.

While Eliza and the Duke struggle around the edges of their relationship, private investigator Nash is shot just as Eliza agrees to work with him.