VASILIY FET, the exterminator with the New York City Bureau of Pest Control, stood at the construction fence above the great “bathtub” foundation at the site of the former World Trade Center complex. He had left his handcart in his van, parked over on West Street, in a Port Authority lot with the other construction vehicles. In one hand he carried rodenticide and light tunnel gear in a red-and-black Puma sport bag. In his other he held his trusty length of rebar, found at a job site once, a one-meter-long steel rod perfect for probing rat burrows and pushing bait inside—and occasionally beating back aggressive or panicked vermin.

He stood between the Jersey barriers and the construction fence at the corner of Church and Liberty, among the orange-and-white caution barrels along the wide pedestrian walkway. People walked past, striding toward the temporary subway entrance at the other end of the block. There was a sense of new hope in the air here, warm, like the abundant sunshine that blessed this destroyed part of the city. The new buildings were starting to go up now, after years of planning and excavation, and it was as though this terrible black bruise was finally starting to heal.

Only Fet noticed the oily smears discoloring the vertical edges of the curb. The droppings around the parking barriers. The gnaw marks scoring the lid of the corner garbage can. Telltale signs of surface rat presence.

One of the sandhogs took him down the haul road and into the basin. He pulled up at the foot of the structure that would become the new underground WTC PATH station, with five tracks and three underground platforms. For now, the silver trains entered through daylight and open air as they made their way along the bottom of the bathtub toward the temporary platforms.

Vasiliy stepped out of the pickup, down among the concrete footings, looking up seven stories to the street above him. He was in the pit where the towers had fallen. It was enough to take his breath away.

Vasiliy said, “This is a holy place.”

The sandhog had a bushy, gray-flecked mustache, and wore a loose flannel shirt over a tucked-in flannel shirt—both heavy with soil and sweat—and blue jeans with muddy gloves tucked into the belt. His hard hat was covered with stickers. “I always thought so,” he said. “Recently I’m not so sure.”

Fet looked at him. “Because of the rats?”

“There’s that, sure. Gushing out of the tunnels the past few days, like we’ve struck rat oil. But that’s fallen off now.” He shook his head, looking up at the slurry wall erected beneath Vesey Street, seventy sheer feet of concrete studded with tiebacks.

Fet said, “Then what?”