“Give me a minute to check the GPS.” After a minute, Sam said, “We’re on it. They would have watered their horses along the riverbed. And if I were a nomadic horseman, I would be sure to take really good care of my horses.” He turned away from the river to face the field. “Fifty to a hundred thousand Hun warriors means something near two hundred thousand horses. It’s hard to imagine what that must have looked like. The line of horses must have stretched along both rivers for a couple of miles.”

Remi wheeled her bike to a nearby tree, leaned the bike against the trunk, stepped on the bike’s lower bar, then the seat, and pulled herself up to the tree’s first large branch. She reached up to the second branch for a handhold and then stood.

“What do you see?” asked Sam.

“From up here, it looks as though the highest part of the field is right over there.” She pointed a hundred yards inland to a section of the field that was slightly elevated.

Sam stepped close and helped her down, then extended the magnetometers’ poles so the sensors extended about three feet in front of the bicycles’ handlebars and the boxes holding the gauges were between the handlebars and easy to read. They walked their bicycles, side by side, into the field and up the slight incline.

It was late afternoon, the sun’s rays falling at a low angle on the field. As they walked they read the magnetometers, watching for disturbances in the magnetic field. There was little fluctuation in the readings until they crossed the highest point in the field, which was almost a dome. Then the needles jumped.

“Did you get that?” Remi asked.

“Got it,” Sam said.

They both stopped. Sam said, “Let’s see how big it is.”

Remi laid her bike down to mark the place where the disturbance began and walked with Sam as he wheeled his bike a few yards. “There,” he said and laid his bike down. They paced the distance together, then replaced the bikes with their sun visors. They rolled the bikes along a perpendicular path. “It’s ten paces by fifteen,” Remi said.

“That’s what I get,” Sam said. “About twenty by thirty feet. Let’s try one of the metal detectors.” Sam assembled the one from Remi’s backpack and began to pass it back and forth over the area they had marked off. It gave off an electronic tone, then a squeal—a loud and unchanging shriek—as he walked the width of the spot.

Remi said, “It’s huge—much bigger than the first chamber. Plan A or Plan B?”

“We’ll have to mark it so we can find it again quickly, then ride back to Peschiera del Garda and get ready to excavate tomorrow night after dark.”

“Where will we find a way to hold a hoard of gold twenty by thirty paces across?”

“We’ve got a navigable river right over there.”

“Aha, Plan A,” she said. “A big boat.”

Sam marked the spot by taking the sensor off his magnetometer and laying the long aluminum pole flat on the ground. Then they rode their bicycles back along the towpath to Peschiera del Garda under the waning sun and then into the darkness.

As soon as they were in their hotel room and had a bath, they called Tibor’s secure cell phone. “Tibor?”

“Yes, Sam.”

“We need the three men we used as crewmen on the boat in the Tisza. They need to be at our hotel in Mantua by tomorrow evening at sundown.”

“You have a boat?” asked Tibor.

“No, but by tomorrow night I will.”

“They’ll be there.”

“Thanks, Tibor.”

“I have to get off now, so I can talk to them. Good-bye, Sam.”

Sam and Remi called the concierge again, and while she got them a reservation for a fine restaurant in Mantua, they drove the twenty-five miles to the city to shop in the best stores and find clothes suitable for an evening out. They began with a gray Armani summer suit for Sam, and, at Folli Follie, Remi bought a simple but striking Fendi jacquard sleeveless dress with a gold accent on the belt. They wore the clothes they had bought, left the clothes they’d worn in the trunk of the car they’d parked at the city walls, and made the ten-minute walk to Ochina Bianca, a restaurant just north of the city’s center.

They ordered risotto alla milanese, redolent with saffron, as their pasta course, osso buco as their entrée, and their wine selection was Felsina Fontalloro 2004 from Tuscany. Remi said, “This is all so wonderful. Let’s flip a coin to see which one of us goes to culinary school so we can have this at home.”

“The cooking part is not my specialty,” he said. “Think of me as your nutritionist and trainer. I’m just helping you build up your strength for tomorrow when the work starts again. In fact, I’m already thinking you might need some dessert. There’s a local delicacy called sabbiosa, which is a plum cake soaked in Guinness. How can that be bad?”

“I have no idea,” said Remi. “Maybe it can’t.”

“In fact, I’ll even have some with you to be sure it’s up to your standards.”

“I’m sure you will.”

After their dinner in Mantua, they walked to the city walls, got into their car, and drove along the country road toward Lake Garda. “I’m glad we did this,” Remi said.

“Are you?”

“Yes. Tomorrow night at this time, if we’re digging a deep hole with shovels, I can remind myself that while the world sometimes brings you dirt and hard labor it also brings perfect risotto.”

“And a perfect date to share it with.”

“You’re getting awfully good at that,” Remi said. “I’m going to have to keep a close eye on you to be sure you’re not practicing compliments on other women.”

“Feel free,” said Sam. “I relish close attention.”

“I know you do,” she said, and leaned close to kiss his cheek as they drove in the starlight back to their hotel in Peschiera del Garda.

CONFLUENCE OF THE PO AND MINCIO RIVERS, ITALY

IT WAS TEN THE FOLLOWING NIGHT BEFORE SAM AND Remi walked into the field again. This time they arrived by car. Sam drove it off the road under the row of trees and bushes and covered it with a tarp to hide its shape. He and Remi wore dark clothes and carried shovels and crowbars, flashlights, climbing ropes, and infrared night goggles in their backpacks.

They quickly found the pole they had left behind and began to dig. The work went more easily than Sam had anticipated because the ground had been plowed recently, so it was loose for the first foot or more. Beneath it was rich black dirt from thousands of years of overflows from the two rivers, land cultivated by the Etruscans and then the Romans, then the Lombards and modern Italians.

It took them two hours to reach a rough stone surface. They dug away some of the dirt on top, moving only enough to make a path to the opening on top. This time, there was not an iron slab but a barrier of three big stones laid close together over the opening and mortared in place.

Remi looked closely at it and said, “This doesn’t look like something we can move by ourselves.”

“It isn’t,” Sam said. “I’ll be right back.”

“What are you doing?”

“Getting the car,” he said over his shoulder. A few minutes later the car they had rented was bouncing along the plowed rows of the field with its lights off. Sam backed up to the edge of the hole he and Remi had dug. He got out, attached the climbing ropes to the tow ring under the car, and looped them over the first of the stone slabs. He took a hammer from the trunk and a crowbar to use as a chisel to chip away most of the mortar. When he was ready, he said, “You drive. I’ll give the stone a little help from back here.”

Remi got into the driver’s seat and opened the window so she could hear Sam.

Sam went to the first of the stones, slid the bent end of the crowbar under its edge, then walked a few yards over to the long aluminum pole from the magnetometer that he had dismantled the day before and came back with it. He slipped it over the long part of the crowbar. The pole was about seven feet long, and he grasped it near the end. “Okay, Remi,” he said. “Slowly.”