They awoke at one, dressed, packed up their fully charged equipment—computer, battery-operated drill, steel drill bits, lights, fiber-optic unit and tubes—into their backpacks and went to Nurin’s room. He was awake and ready, with the five-piece box already lying flat in the car trunk. He drove them to the green market and helped them carry the pieces to the deserted spot.

The awnings of the stalls were still up, but the tables and bins were now empty. Stores along the edges of the market were all locked up, with sliding gates across their fronts to prevent burglaries. There were lights on in some of the streets beyond the shops, but the contrast kept the marketplace in deeper darkness beneath its awnings and roofs.

Nurin helped Sam and Remi assemble the black box, and then Sam patted Nurin’s arm and pointed in the direction of his car and Nurin walked away.

As soon as Nurin was gone, Sam took the magnetometer out and Remi connected the laptop to it. They walked a few yards up the aisle and back to recheck the exact spot where the variance in the magnetic field began and ended. They repositioned their black box in a space directly above the anomaly. It looked exactly like one of the market’s stalls. Then Sam lifted the hinged section of the box to let Remi crawl in while he packed the magnetometer into his pack and removed other equipment and then joined her inside the box.

The space was cramped, but he had designed the box to give himself just enough space for the moves he would need to make. He attached a drill bit with a four-foot shaft that had been designed for drilling through thick logs and beams. Then he positioned the bit in the ground and began to drill. The market was mostly fine, sandy dirt that had been packed down by the weight of many shoes. It took him little time to get down to a depth of four feet. When his drill was almost to the ground, he loosened the chocks to eject the shaft, then took the next shaft, which Nurin had paid a machinist to attach a screw to, and attached it to the first shaft. Then he attached this extended shaft to the drill and kept drilling. About six feet down, he reached a hard surface.