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.