Inside was the thin manila folder containing Daniel Hayes’s personal papers.

Among them was the last letter my biological father had written before his vehicle went over the ridge in Germany.

I spread the yellowed pages across the center console.

The paper was thin, almost translucent, smelling of cedar and old dust.

Eleanor reached out, her fingers hovering just above the handwriting.

“He wrote this the night before he died,” she whispered.

“I know,” I said.

I turned on the overhead map light.

The handwriting was neat, disciplined, and written in blue ballpoint ink.

To an outsider, it was a standard letter of farewell, filled with regrets and wishes for my future.

But Daniel Hayes had been a logistics specialist for the Defense Intelligence Agency.

He did not write anything without a secondary purpose.

I studied the first page.

Certain letters had small, almost imperceptible dots beneath them.

“Did he ever send you coded messages when he was deployed?” I asked.

Eleanor looked up from the paper.

“Only when he was working on sensitive contracts,” she said. “He used a grid system.”