If Caroline was going to make any sense of this letter, she needed another pair of eyes to help. Maybe she was too close and emotional to interpret whatever Luke was trying to say to her.

That meant she needed Nathaniel. He was a detective. He had an eye for detail and might be able to spot something she’d overlooked.

Except that ever since l’affaire de lobster, he had been assiduously avoiding her. He was scrupulously polite and professional, but it was clear he intended to honor the president’s request and keep his distance.

At dinner that night, he dined with Sven de Haas, Alfred Medina, and a pair of AP reporters. Dessert was an amaretto cake, but the real treat was a gourmet selection of cheeses paired with wines. Nathaniel rarely drank, and she pounced on her opportunity to get him alone.

“Can I ask you to come to the parlor car?” she asked.

He immediately went on alert. “Why?”

“I need your professional opinion on something.” It was impossible to ignore the knowing glances flying among the men, and she met them head on. Turning to the maddening Sven, she kept her voice loud enough for everyone in the dining car to hear. “I shall naturally be on good behavior and keep my hands to myself, so Mr. Trask’s spotless reputation will remain unsullied.”

Mercifully, Nathaniel rose without qualm and followed her through to the parlor car. It was dim, and he immediately turned the dial on the gas lamp to glow brighter.

His face was drawn with concern as he turned to her. “How’s your brother?”

It felt entirely natural. They knew each other so well that he didn’t even need to ask what her worries were.

“Not good,” she said, handing him the letter. “His last letter is nonsensical, and Gray thinks he’s losing his hold on the world around him. I’m not so sure. I wonder if he’s trying to communicate something, but I can make no sense of it. I need a fresh pair of eyes.”

Nathaniel sat on one of the padded benches to read, and she watched as his eyes traveled over the puzzling text. She didn’t even need to explain her concerns to Nathaniel, as he immediately began breaking down the passages.

“The city of columns is Havana,” he said.

“How do you know that?”

“Havana has always been known as the city of columns because of all the Spanish architecture.”

She looked at the passage Luke had written. The crew from the north has vanished, and the road to a city of columns is in danger.

“Havana is in danger?” she asked.

“No, the road to Havana is in danger, and the trouble is coming from ‘the westernmost key.’ Does Luke have any connections in Key West?”

“Not that I know of.”

“Who is the good dancer?” Nathaniel asked.

“I am, but he is too.”