Caiden crept to the machine’s rust-eaten rim, twelve meters above where his father’s wiry figure stood bristling with tools.

“I need a break!” Caiden wiped his eyes, smearing them with black grease he noticed too late. Vertebrae crackled into place when he stretched, cramped for hours in ducts and chemical housing as he assessed why the aerators had stopped working so suddenly. From the aerator’s top, pipes soared a hundred meters to the vast pasture compound’s ceiling, piercing through to spew clouds of vapor. Now merely a wheeze freckling the air.

“Well, I’m ready to test the backup power unit. There are six more aerators to fix today.”

“We haven’t even fixed the one!”

His father swiveled to the compound’s entrance, a kilometer and a half wide, where distant aerators spewed weakened plumes into the vapor-filled sky. Openings in the compound’s ceiling steeped the empty fields in twilight while the grass rippled rich, vibrating green. The air was viciously silent—no more grunts, no thud of hooves, no rip and crunch of grazing. A lonely breeze combed over the emptiness and tickled Caiden’s nose with another whiff of death.

Humans were immune to the disease that had killed every bovine across the world, but the contaminated soil would take years to purge before new animals were viable. Pasture lots stood vacant for as far as anyone could see, leaving an entire population doing nothing but waiting for the overseers’ orders.

The carcasses had been disposed of the same way as the fat bovines at harvest: corralled at the Flat Docks, two-kilometer-square metal plates, which descended, and the livestock were moved—somewhere, down below—then the plate rose empty.

“What’ll happen if it dissolves completely?” The vapor paled and shredded dangerously by the hour—now the same grayish blond as Caiden’s hair—and still he couldn’t see through it. His curiosity bobbed on the sea of fear poured into him during his years in the Stricture: the gray was all that protected them from harm.

“Trouble will happen. Don’t you mind it.” His father always deflected or gave Caiden an answer for a child. Fourteen now, Caiden had been chosen for a mechanic determination because his intelligence outclassed him for everything else. He was smart enough to handle real answers.

“But what’s up there?” he argued. “Why else spend so much effort keeping up the barrier?”

There could be a ceiling, with massive lights that filtered through to grow the fields, or the ceiling might be the floor of another level, with more people raising strange animals. Perhaps those people grew light itself, and poured it to the pastures, sieved by the clouds.

Caiden scrubbed sweat off his forehead, forgetting his grimy hand again. “The overseers must live up there. Why else do we rarely see them?”