They rode their new bicycles back to their hotel, then walked them into the elevator and took them to their floor. When they had the bicycles in their room, he attached the magnetometers in such a way that no one looking at the bicycles would know that there was anything unusual about them. The telescoped magnetometer poles looked like reinforced bicycle crossbars, and the sensors extended just a few inches in front of the handlebars.

He removed the two metal detectors from their boxes but kept them stored unassembled in the two backpacks.

As they were preparing, Sam’s cell phone buzzed. He switched on the speaker. “Yes?”

“Sam? It’s me, Albrecht.”

“Are you in California yet?”

“Yes. I’m in your house, with Selma. Since I left you, I’ve spent some time studying the available satellite photography and aerial mapping of the spot where you’re looking, and I’ve rechecked some of the written sources.”

“What can you tell us?”

“There are several versions of the story but a few things we know for certain. One is that Attila left a trail of destruction in the northern part of Italy and came down the west side. There were no roads on the east side until the 1930s, which is an indication of what the landscape is like.”

“Remi figured that out,” said Sam. “And since the Huns didn’t leave a written history, we’re guessing the best sources are the people who kept track of Pope Leo I. They list the cities Attila sacked and destroyed. Mantua is the last one.”

“Leo met him on the Mincio where it empties into the Po. The Pope had come from the southeast, and since he was the supplicant, he went to Attila’s camp.”

“How will we know where the camp was?”

“Your coordinates are 45° 4' 17.91" north, 10° 58' .01" east. Attila had between fifty and a hundred thousand fighters. That means at least a hundred thousand horses and innumerable cattle, sheep, and goats. They would be lined up along the river, drinking and grazing. The encampment would be on a fairly flat piece of ground, but elevated to keep from flooding.”

Selma said, “We put the camp’s tents about two hundred yards from the confluence, stretching west along the north side of the Po.”

Remi said, “Why the north side?”

“Attila had just come down from the north, and they knew that no force was left behind them. The only possible threat would have been a Roman army somewhere to the south, so they would have kept the river to the south of them as a barrier.”

“Okay,” said Remi. “North side of the Po, west side of the Mincio. Flattish ground, look for the highest spot on it.”

“That’s right,” said Albrecht. “We’re still trying to decide how Attila’s men could have buried the treasure secretly.”