He climbed out and went to the nearest row of grapevines, where there were wooden stakes with sixpenny nails driven partway in to hold the wires for the vines. He began to pull the nails out. Sam looked closely at each one, twirled it in his fingers. He put some in his pocket and rejected some, pushing them back into the holes in the stakes.

“How many do you want?” asked Remi.

“Thirty or forty. Don’t take any that are bent.”

Albrecht and Remi collected nails until Sam said, “That’s enough to test the theory.” They all got back in the hole.

“Now we use our spades to try to pry up one end. A quarter inch will do.”

They pried an end up, and Sam held his spade down with one hand and bent to insert a nail sideways between the iron sheet and its stone base. Once one was in, he could insert twenty others without much strain. They repeated the process on the other end of the slab. Albrecht said, “Your theory is sound. Let’s hope your rollers are big enough.”

Sam knelt at one side of the slab of iron and moved it easily aside, rolling on the sixpenny nails. The three looked down through the opening with their night vision goggles. Albrecht said, “This isn’t what I expected. It looks like a stone room.”

“Let’s hope it’s not an air-raid shelter,” said Remi. “Or a septic tank.”

Sam said, “I can see part of the floor.” He took off his belt and slipped it over the handle of his spade and through the buckle. “Each of you hold one end of the spade and I’ll lower myself down a bit and jump.”

Remi put her hand on his shoulder. “Sam, I weigh eighty pounds less than you do.” She took the end of the belt and sat at the edge of the opening. She pushed off, rappelling down a few feet, then extended her arms and hung from the belt. Then she dropped into the darkness.

They heard the soft thud of her feet hitting the stone floor. There was silence as she walked into the part of the stone room where they couldn’t see her.

“Remi, talk,” Sam said. “Just so I know it wasn’t full of carbon monoxide, or fifty-year-old nerve gas.”

“It’s full of . . . nothing.”

“You mean grave robbers have been here?”

“I don’t think so,” she said. “Grave robbers are messy. Wait. There’s another big piece of iron. This one’s only tarnished, not much rust. It’s got something carved in it. Looks like Latin.”

“The Romans are my regular specialty,” said Albrecht. “I’ve got to see it.”

“Here. Hold on,” said Sam. “Exactly the way Remi did it.”

Albrecht held the belt and eased himself over the edge, then held on and rappelled a few steps, hung, then dropped the last couple feet.

Sam put the three spades together like spoons, slipped his belt around them and through the buckle, and propped them across a corner of the opening. He then lowered himself down.