Eliza eventually discovers that the insurance company that hired her is a front for a "dodgy lawyer" and that the case involves fraud.

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

William is forced to mentor a new, "privileged" apprentice detective, Oliver Fitzroy, whose father is a high-ranking official at Scotland Yard.

The sketch was stolen from a small natural history museum run by Mrs. Garret. Key Plot Points

The story is set in 1882, shortly after Darwin's death, which has caused the value of his original artwork to soar.

William "The Duke" Wellington is officially investigating the theft for Scotland Yard, putting him in direct competition with Eliza.

The episode uses the folklore of the actual black witch moth as a thematic backdrop. In reality: