“So you have a probable date and location—does that help?”

“It might, but not as much as this.” Patton pointed to the two words barely visible in faint pencil at the top of the page.

“Projekt Alchemie,” read Nemo. “What does that mean?”

“If we’re lucky, that’s the beginning of our crib,” said Patton. “Maybe before the Americans showed up, that teenage SS officer was decoding the message.”

“Yes, but what does it mean? In English, I mean.”

“I don’t know a lot of German,” said Patton, “but I’d say it means that the Nazis were working on alchemy. Or at least someone in the SS was.”

“Alchemy?” said Nemo. “You mean some medieval nonsense about turning lead into gold?”

“Yeah, only I doubt the Nazis would call it nonsense. A lot of the higher-ups believed in all sorts of bizarre stuff—witchcraft, parapsychology, the Holy Grail, the lost city of Atlantis. Didn’t you ever see Raiders of the Lost Ark?”

“I don’t get out much,” said Nemo.

“Well, it wouldn’t surprise me if the Nazis fooled around with alchemy.”

“And you think they discovered how to turn lead into gold?” said Nemo, a hint of sarcasm in his voice.

“I doubt that,” said Patton, “but it would explain why someone is so eager to get their hands on this message.”

“Look, I may have led a . . . different sort of life, but even I know that turning lead into gold is nonsense. It is nonsense, right?”

“Hey, I’m no scientist,” said Patton.

“And what exactly are you?” said Nemo. “Because I know you’re something more than a small-town librarian who isn’t a scientist.”

Patton smiled and turned her attention back to the Enigma message, but Nemo wasn’t done asking questions.

“And how is it you know so much about decoding secret messages from seventy years ago?”

“I could tell you,” said Patton, looking Nemo directly in the eye, “but then I’d have to kill you.”

That sentiment had come close to being the truth, thought Patton, recalling the day toward the end of her graduate studies when she had been called into an empty office in the basement of the university library and met two men in dark suits. They sat behind a table and asked her to sit down. Out of curiosity more than fear or obligation or the intimidation they seemed to be trying to wield, she did.

“Patton Jackson Harcourt,” said the man on the left. “A good military name.”

“I come from a good military family,” said Patton. “We’re like that guy in Forrest Gump—you know, the one whose family has lost sons in every American war?”

“And you are a talented mathematician with a particular interest in . . . shall we call it the history of military codebreaking.”

“A casual interest. I went to a conference last summer.”

“And distinguished yourself according to . . .”