Dr. Chisholm steps over a small sand dune and approaches me. I hadn’t realized that he wasn’t around while we were watching the bomb robot cut open the plane.

“Your idea?”

I can tell he means the thumb. “It seemed . . . pragmatic.”

“Probably the safest thing to do at this point.” He looks over his shoulder at the crowd behind the barrier.

“Anything interesting?” I ask.

Chisholm turns his attention to the plane and speaks in a low voice. “We’ve got plainclothes out there taking photos of everyone and photographing all the license plates we can find. Hotel records too. Of course in a crowd this size . . .” He glances back over his shoulder. “At least three thousand people now. We can expect at least sixty clinical sociopaths. Maybe more because it’s a workday and these people don’t seem to have anything else to do. At least several hundred convicted felons and God knows what else are out there.”

“You must be a blast at a football game.”

“Forty.” He throws the number out there for a moment. “That’s how many people in an average football stadium have murdered someone in the last ten years.”

“And that’s just when the team shows up to practice,” I reply.

Chisholm lets out a laugh. Not too loud, but genuine. “You have a dark sense of humor, Blackwood.”

“You should meet my family.”

“I have. Your grandfather signed an autograph for me when I was a boy. I was a little magician myself. Just a magic set. Nothing serious. Nowhere near your level. Never had much coordination. I loved seeing how adults could be fooled. That’s what got me into psychology. When I realized that some people thought magically all the time, thought angels or dogs were talking to them, whispering for them to kill, I didn’t need trick decks anymore.”

“Me neither, I guess.” I didn’t know he’d met my grandfather. I wonder what he makes of me and my career choice.

“So, as a former magician, what’s your reaction going to be if the thumbprint comes back as a match?”

“You mean am I going to believe that a man vanished in the middle of last century, only to reappear just as young as the day he died?”

“What else is there?”

“Somebody switched the paper card in the basement of the Pentagon with the fingerprints on it.”

“Really?” replies Chisholm. Is he skeptical?

“I could do it with fifty bucks and a sheet of fake letterhead from a university.” I’m thinking of a stunt my father pulled on the New York Times by planting something in its archives when they were still physical. I’m sure doing the same at the Pentagon is an order of magnitude more difficult, but they all have the same weaknesses: people. Records like that aren’t national secrets.

“Occam’s razor. Fair enough. Assuming the uniform and badges is war surplus. What about the plane? What if it holds up when we put all those serial numbers under our electron microscopes and start looking for aging in the abrasions on the metal inside the grooves of the etching?”