In this magical tale of self-discovery from New York Times bestselling author Carrie Vaughn, a young widow taps into the power that will change the world--if the man's world she lives in doesn't destroy her and her newfound friends first.

In the summer of 1880, the death of Beth Stanley's husband puts her life's work in jeopardy. The magic of Arcane Taxonomy dictates that every natural thing in the world, from weather to animals, can be labeled, and doing so grants the practitioner some of that subject's unique power. But only men are permitted to train in this philosophy. Losing her husband means that Beth loses the name they put on her work--and any influence she might have wielded.

Brandon West and Anton Torrance are campaigning for their expedition to the North Pole, a mission that some believe could make a taxonomist all-powerful by tapping into the earth's magnetic forces. Their late friend Harry Stanley's knowledge and connections would have been instrumental, but when they attempt to take custody of his work, they find that it was never his at all.

Tied together by this secret and its implications, Beth, Bran, and Anton must find a way for Beth to use her talent for the good of the world, before she's discovered by those who would lay claim to her rare potential--and her very freedom.