As she rounded a final oxbow in the Mississippi River, the compound appeared ahead. The Audubon Center for Research of Endangered Species occupied more than a thousand acres downriver from New Orleans. Though associated with the city’s zoo, ACRES was not open to the public. Sheltered within a hardwood forest, the grounds included a few outdoor pens, but the main facility was a thirty-six-thousand square-foot research building that housed a half-dozen laboratories and a veterinary hospital.

The latter was where Dr. Lorna Polk had worked since completing her postgraduate residency in zoo-and-wildlife medicine. She oversaw the facility’s frozen zoo, twelve tanks of liquid nitrogen that preserved sperm, eggs, and embryos from hundreds of endangered species: mountain gorillas, Sumatran tigers, Thomson’s gazelles, colobus monkeys, cape buffalo.

It was a big position to fill, especially for someone only twenty-eight and just out of her residency. Her responsibility-the frozen genetic bank-held the promise of pulling endangered species back from the brink of extinction through artificial insemination, embryo transfer, and cloning. Yet, despite the weight of her responsibility, she loved her work and knew she was good at it.

As she raced down the long entry road toward the main facility, her cell phone chimed from the cup holder. She grabbed it and cradled it to her ear while driving one-armed.

The caller must have heard the line pick up and spoke rapidly. “Dr. Polk. It’s Gerald Granger from engineering. I thought you should know. We’ve got the generators working and isolated the power loss to a downed line.”

She glanced to the truck’s clock. The power had been down for close to forty-five minutes. She calculated in her head and let out a sigh of relief.

“Thanks, Gerald. I’ll be there in another minute.”

She flipped the phone closed.