The mountains were soon nothing but distant purple shadows, cloaked in hot haze. Tractor trailers made up most of the traffic on the road. Occasionally they passed a car or a pickup truck whose driver would stare at the unlikely group. Jose pulled over for gas outside a small town built from corrugated metal and crumbling concrete. He came out from paying at the station carrying a plastic bag filled with sweaty water bottles. They chugged the water and got back onto the highway. Soon, on the horizon ahead, a brown-and-yellow cloud appeared. Off toward the east, a bruised sky brooded and flickered with lightning.

Jose pulled off the highway, stood up with his hands on the windshield, and studied the sky. Big tractor trailers whooshed by without slowing, whipping them with streams of grit and dust.

"Weather usually comes west to east," he said, glancing back at Casey and giving her a knowing nod toward Isodora and her baby. "Why it's coming from the wrong direction and what it means, I don't know. I think we can beat it. If it looks bad, we'll have to get off and find a hotel, fast. What do you think?"

"Let's try," Casey said. "I'd like to at least make it across the border before we stop."

Jose fell back into his seat and ground the gears, bringing the jeep back up to speed. They crept toward the brown cloud of smoke and soon saw that its source lay just beyond a low rise of hills where the land began to dip toward the Rio Grande. They had nearly reached Nuevo Laredo when Casey sniffed the air and poked Jose's shoulder.

"You smell that?" Casey said, shouting above the whine of the jeep and the flap of air.

Jose nodded. "Stinks like hell."

"I can taste it," Casey said, studying the hills and just making out the glint of a metal stack.

The road soon rose and in a cleft between two hills, the factory made itself known on the plain below. Power lines running alongside the road detoured down to it and a wide stone road ran perpendicular to the highway. Shiny metal gates guarding the road and the fence, all of fourteen feet and capped with loops of concertina wire, stretched off into the distance, marking the boundaries of the place. Casey squinted and stared at a single pale blue sign whose words she could not read. Beyond, the storm rolled toward them. Above, the heavy brown swell of filthy air swirled and grew.

Jose pulled off the road and rose from his seat. Casey stood on the back of her seat, a full foot higher than Jose.

"The priest said a factory up north," she said, her face directed into the coming wind. "You don't think?"

Thunder rumbled from a distance.

"I think most times people wouldn't smell it like this," Jose said, "but the wind's just right, coming out of the east with this storm. A drug factory? Why not? That smell, God, it's awful."

Casey had her hand over her mouth and nose. She took out her cell phone to take a picture. As she did, the bark of a siren made her jump. A black police car with white doors had pulled off the highway behind them, its blue-and-red lights flashing. Two federales in blue uniforms and shiny midnight hats jumped out and scrambled up alongside the jeep with their hands on the holsters of their guns.

They barked out orders that Casey didn't understand. She looked to Jose, who glared back at the cop closest to him. Isodora clutched her baby tight and whined.

"What the hell do they want?" Casey said.

Before Jose could answer, the cops drew their guns and began to shout.

THE COP BEHIND CASEY SNATCHED THE PHONE FROM HER HAND and dropped it to the ground before he stomped and ground it, crackling, beneath his heel. Jose had his hands in the air and Casey did the same. Jose talked calmly to the cop pointing a gun at him.

"Jose?" Casey said, her voice frantic.

"Relax," he said. "Get out slow and keep your hands up."

Jose stepped out of the jeep and away with his hands in the air. Casey did the same and Isodora climbed out, too.

"Where's your ID?" Jose asked.

"My purse," Casey said, nodding. "It's on the floor."

Jose spoke to the cops. The second cop fished Casey's purse from the floor of the jeep while the first kept his gun trained on Jose. Isodora stood beside Casey with the baby in the gritty roadside dust. The cop threw the purse on the hood and rifled through it, finding Casey's passport as well as Isodora's visa. He found Casey's wallet and extracted the cash, holding it up for his partner, who offered only a stony nod. The second cop then removed Jose's wallet and passport from the front pocket of his jeans, studied the picture, and took his cash as well.

The cops patted them down, then Jose went back and forth with them for several minutes as they examined the documents. At one point the first cop looked Isodora's way and barked a question at her. Startled, she replied in barely audible Spanish. They turned their attention back to Jose and their conversation got heated before eventually cooling. Finally Jose lowered his hands and stepped toward the jeep.

"Come on," he said to Casey. "Come on, Isodora. Get in the jeep."

"Didn't you tell them you were a cop?" Casey asked in a low voice as they climbed aboard the jeep. Some of her hair had escaped and the hot wind whisked it across her face until she tucked it back.

"That's why they were so nice about it," Jose said, reaching back to give Isodora's leg a reassuring pat before he started the engine.

"What? Not shooting us?" she asked.

"They let us go," Jose said, looking back. "That's what counts."

"Swell."

"Said that's a military facility," Jose said. "No stopping. No pictures. They saw your phone."

"Military, my ass," she said. "Making what? Biological weapons? They're burning off something and it isn't gunmetal."

Jose put the jeep in gear and said, "They wanted to know about Isodora."

"What did you say?"

"The truth," Jose said. "Her husband died and we're taking her back to testify in a lawsuit."

"That's all you said?" Casey asked.

"No, I told them we were out to destroy a US senator," Jose said, flashing her a look. "Come on."

"They gave me the creeps," Casey said. "And that place? That place is something bad."

Jose glanced to his right, then returned his attention to the road.

"Looks like we're going to beat the storm," he said. "It's still a ways off."

Fifteen minutes later the Nuevo Laredo traffic got heavy. That's when Jose pointed out the helicopter.

"What? You think it's following us?" Casey said.

"It's not a traffic copter," Jose said. "It's not TV. It's police, or some kind of government job."

"Because I took a picture that I now don't even have? Come on."

Jose shrugged. "Maybe nothing to do with us. I've been watching it for about the last five minutes, though. It hasn't gone very far."

By the time they got through the heavy traffic in town, the helicopter had disappeared.

"Big Brother went home," Casey said.

"Guess so."

"Better to be aware than not," Casey said.

"That's what I thought."

The customs agent barely looked at their papers before swigging her Diet Coke and waving them through, one small segment in the snake of trucks and cars waiting to enter the United States. The wind had picked up enough for them to find a branch of their rental company just off Route 35 at Laredo Airport, drop off the jeep, and pick up a four-door sedan with air-conditioning that they could drop off in Dallas. No sooner had they pulled back onto the highway than the sky opened up, dousing the windshield with buckets and lighting up the darkened sky all around them with flashes of chain lightning.

Jose drove while the rest of them dozed. He took them to Casey's place, where they all had eggs and bacon, even the baby. Then Isodora and the baby disappeared into Casey's guest room, and Casey took two longneck bottles of Budweiser from the fridge and sat down on the couch next to Jose.