Scarlett Knox

Norfolk, Virginia, 1942. Alma Deming inspects film for a living, and she is very good at it. She is also the most effective German agent in North America, and nobody is looking for her, because she has never sent a signal in her life. No radio. No invisible ink. No coded words on paper that a censor could develop. Instead she draws. Two hundred ruled lines of black ink on white card, photographed down onto eleven inches of film and spliced into the head leader of newsreels that the United States government ships to South America at its own expense.
Anti-Nazi pictures, carrying her convoy sailings, delivered by the country she is betraying. Then a half-deaf projectionist at a naval base hears a tick in reel one that should not be there. He writes to the exchange about it three times. Nobody answers him. He is not clever and he is not suspicious. He is only careful, and careful is worse. By the time an auditor arrives from the home office to investigate a rise in print damage, Alma has learned the shape of her own danger.
The people who threaten her are never the ones who understand what they have found. They are the ones who are about to mention it to somebody who would. She keeps the count in a coffee tin on a shelf, between the buttons and the shoe polish.