The episode uses the folklore of the actual black witch moth as a thematic backdrop. In reality:
The story is set in 1882, shortly after Darwin's death, which has caused the value of his original artwork to soar.
Eliza Scarlet is hired by an insurance firm to track down a rare, valuable sketch of an Ascalapha odorata (the black witch moth) drawn by Charles Darwin himself during his 1835 voyage to the Galapagos Islands. [S2E2] The Black Witch Moth
William "The Duke" Wellington is officially investigating the theft for Scotland Yard, putting him in direct competition with Eliza.
The episode highlights Eliza's struggle for professional respect; she is initially rejected by a women's cultural society because of the "caliber" of her clients. The Real Black Witch Moth The episode uses the folklore of the actual
The sketch was stolen from a small natural history museum run by Mrs. Garret. Key Plot Points
Eliza eventually discovers that the insurance company that hired her is a front for a "dodgy lawyer" and that the case involves fraud. Garret
William is forced to mentor a new, "privileged" apprentice detective, Oliver Fitzroy, whose father is a high-ranking official at Scotland Yard.