Reaching the employee lot, she parked and rested her head on the steering wheel. The relief was so palpable she almost cried, almost. After taking a moment to collect herself, she straightened and stared down at the hands on her lap, suddenly aware of what she wore. She had fled the house in a pair of wrinkled jeans, an old gray turtleneck, and boots.

Not exactly the professional appearance she usually maintained.

Twisting to exit the Bronco, she caught her reflection in the rear-view mirror.

Oh, dear God…

Her blond hair-normally primly braided-had been pinned back into a rough ponytail this morning. Several flyaways only added to her already disheveled appearance. Even her black-framed glasses sat askew on the bridge of her nose. At the moment she looked like a drunken college student returning from a Mardi Gras party.

If she looked the part, she might as well go all the way. She pulled out the pin holding her hair and let it fall around her shoulders, then climbed out of the truck and crossed toward the main entrance.

Before she could reach the facility’s front doors, a new noise drew her attention: a heavy wump-wumping. She turned toward the Mississipi. A white helicopter skimmed over the tree line and headed in her direction. It was coming in fast.

As she frowned, a hand settled on her shoulder from behind. She jumped slightly, but fingers squeezed in reassurance. A glance back revealed her boss and mentor, Dr. Carlton Metoyer, the head of ACRES. Covered by the noise of the helicopter, she had not heard his approach.

Thirty years her senior, he was a tall, wiry black man with bushy white hair and a trimmed gray beard. His family had been here in the region for as long as Lorna’s, tracing their roots back to the Cane River Creole colony, a blend of French and African heritage.

Dr. Metoyer shielded his eyes as he stared at the sky.

“We got company,” he said.

The helicopter was definitely headed toward ACRES. It swept toward an adjacent field and began to descend. She noted it was a small A-Star helicopter equipped with floats instead of the usual landing skids. She also recognized the slash of green across the white shell of the aircraft. After Katrina, most people in New Orleans knew that insignia. It was one of the Border Patrol helicopters; fleets of such choppers had been vital to the rescue operations and security following the disaster.

“What are they doing here?” she asked.

“They’ve come for you, my dear. They’re your ride.”

Lorna’s stomach sank as the helicopter lifted off-not so much from the motion as from sheer panic. She clutched the armrests as she sat next to the pilot. The growing roar of the rotors penetrated her bulky headphones. It felt like rising in an elevator. An elevator strapped to a rocket.

She had never been a fan of heights, hated air travel in general, and considered riding an airborne lawn mower the height of madness. She had only flown once in a helicopter, during an externship in South Africa conducting a census of African elephants in the lands bordering a preserve. Back then, she had prepared for that flight by downing a pair of Xanax tablets before the trip. Still, her legs had felt like warm pudding for hours afterward.

And today she’d had no warning.

Dr. Metoyer had only filled her in on the sketchiest of details as the helicopter landed. He had not even given her time to go inside and inspect her project’s liquid nitrogen tanks. Staff is already on it, he had promised, adding that he’d check them himself and radio the details later.

Radio…

They were flying beyond any cell signal.

She risked a glance through the side window. The helicopter banked, giving her a bird’s-eye view of the Mississippi. They were traveling downriver, roughly following the Big Muddy’s course. The name was particularly apt following the storm. The river was a chocolate brown, rich with silt, eddying and churning as it flowed toward the Gulf of Mexico.

They were headed out over the river’s delta, where all that alluvium-silt, clay, sand, and soil-deposited and pushed out into the Gulf, forming over three million acres of coastal wetlands and salt marshes. Not only was the region environmentally significant, home to a vast and complicated ecosystem that traced its roots back to the Jurassic period, it was also commercially significant. The area supplied the United States with a large percentage of its seafood, and almost 20 percent of its oil.

It was also a weak link in the nation’s border. The maze of islands, twisting waterways, and isolated fishing docks made the delta a sieve for smugglers and traffickers of all sorts. The Department of Homeland Security had designated the region a high-level threat and reinforced the New Orleans station of the Border Patrol.

According to her boss, the Border Patrol had been searching the area following last night’s storm surge. It was common for smugglers to work under the cover of storms to bring in drugs, guns, even human cargo. Early this morning, a team had discovered a trawler beached on one of the outlying islands. After investigating the ship, they’d made a call to ACRES.

Much of that call remained a mystery, even to Dr. Metoyer. He had not been informed about the nature of the request, or why Lorna in particular had been asked to make this trip.

Despite her trepidation about air flight, a smoldering anger was building. She had projects in jeopardy over at ACRES. What was she doing flying out into the middle of nowhere? Her anger grew, stoked by her anxiety. What was going on? Why ask for her in particular? She knew no one in the Customs and Border Protection service.

The only answers lay at the end of this flight.

The radio built into her earphones crackled. The pilot pointed toward the horizon. He wore a green uniform with shoulder patches marking him as part of the Border Patrol’s Air and Marine unit. He had introduced himself, but she hadn’t caught his name.

“Dr. Polk, we’ll be landing in a few moments.”

She nodded and stared forward. The dense emerald of the swampy marshes broke apart below into a tangle of islands and peninsulas ahead. Farther out into the Gulf, a dark line near the horizon marked a row of larger barrier islands that helped protect the fragile marshes and coastal swamps.

But they weren’t going that far.

She spotted a shiny white boat moored by one of the small islands. Finally. As they descended toward it she also noted an old fishing trawler rammed into the beach. It had struck hard enough to topple a few trees and ride halfway up onto the island. It plainly had been shoved there by the storm surge.

The helicopter dropped fast. Her grip tightened on the armrests. She had read that a majority of air crashes occurred during takeoffs and landings. Not a statistic she wanted to bear in mind at the moment.

Within a few yards of the water, their descent slowed. The rotor-wash beat the waves flat. Then, as gently as a goose landing on a still pond, the chopper’s floats settled to the water. A few flicks of some switches and the whine of the rotors began to slow.

“Please stay seated,” the pilot said. “They’re sending a Zodiac out for you.”

His nod out the window drew her attention to a small rubber pontoon boat that pushed off from the island and shot toward them. Moments later, a crewman dressed in the same Border Patrol green helped her out of the helicopter and into the Zodiac.

She dropped onto a bench of the pontoon boat, both relieved yet still carrying a hot coal in her belly. She shaded her eyes as they headed toward shore, searching for some answer for the mysterious and sudden summons.

The morning was already growing warm as the sun broke apart the clouds and opened blue skies. The day promised to grow into one of Louisiana ’s steam baths. And she was okay with that. She took deep breaths to steady herself, taking in the brackish odor of leafy decay, wet moss, and muddy salt water.