Alex stripped off her pants and shirt, walked out to the empty pool, and started swimming laps in her underwear. It was too late for anyone decent to complain, and if a Bill Fennell type wanted to sit on the plastic furniture and ogle her ass while she worked out her frustration, then he was welcome to it. If he was still there when she got out, she'd kick his butt across the parking lot.

Dr. Eldon Tarver walked slowly along the park path, his big head down, his eyes in a practiced state of general focus, searching for feathers in the tall grass. In one hand he carried a Nike duffel bag, in the other an aluminum Reach-Arm device, used by most people for picking up soda cans and litter from the ground. But Dr. Tarver was not like most people. He was using the Reach-Arm to pick up dead birds, which he then sealed inside Ziploc bags and dropped into the Nike duffel. He'd been out since before dawn, and he'd bagged four specimens already, three sparrows and a martin. Two seemed quite fresh, and this boded well for the work he would do later in the morning.

Dr. Tarver had seen only two other humans so far, both runners. Not many people ventured into this corner of the park, where branches hung low to the ground and the path was overgrown in many places. The doctor had startled both runners, partly by his simple presence at this place and time, but also because of his appearance. Eldon Tarver would never be mistaken for a runner.

He was not dressed in shorts or warm-ups, but in cheap slacks and a pullover from the Casual Male Big amp; Tall shop on County Line Road. Dr. Tarver stood six feet three inches tall, with a barrel chest and ropy arms covered with black hair. He had been bald since the age of forty, but he wore a full gray beard that gave him the look of a Mennonite preacher. He had preacher's eyes, too-not parson's eyes, but the burning orbs of a revealed prophet-bright blue irises that shimmered in the center of their dark sockets like coins at the bottom of a well. When he was angry, those eyes could burn like the eyes of a demon, but few people had ever seen this. More often, his eyes radiated a glacial coldness. Some women at the medical center thought him handsome, but others called him downright ugly, this impression being bolstered by what most people thought was a wine-stain birthmark on his left cheek. The disfiguring mark was actually a severe arteriovenous anomaly, a horror that had begun mildly during childhood but which during puberty had flamed to the surface like the sign of a guilty conscience. All these qualities had combined to make even the large male runner jig five steps to the right as he passed, for it took five steps to get clear of the bearded giant ambling along the path with his aluminum stick and duffel bag.

As the first yellow rays of sunlight spilled through the oak limbs to the east, another runner appeared-a girl this time, a vision in tight blue Under Armour with white wires trailing from her golden hair. The wires disappeared into an iPod strapped to her upper arm. Dr. Tarver wanted to watch her approach, but just then he noticed another bird off the path, this one twitching in its death throes. It might have fallen only seconds ago.

The girl's shoes swished through the dewy grass as she left the asphalt path on the side opposite the doctor. She tried to make it appear as though she'd done this out of courtesy, but she could not deceive him. He divided his attention between the girl and the bird, one filled with life, the other dying fast. She tried not to look at him as she sprinted past, but she couldn't manage it. Twice her pupils flicked toward him, gauging the distance, making sure he hadn't moved closer. Threat assessment was such a finely tuned gift, one of the blessings of evolution. He smiled as the girl passed, then turned and regarded her flexing glutes as they receded from view, appreciating their shape with the cool regard of an expert anatomist.

After she'd vanished around a bend, he stood still, breathing the wake of her perfume-an ill-advised accessory for morning jogs if one wanted to avoid unwelcome attention. After the fragrance had dissipated beyond detection, he knelt, donned surgical gloves, and withdrew a scalpel, a syringe, and a culture dish from his pocket. Then he tied on a surgical mask and laid open the sparrow's breast with a single incision. With a long finger he exposed the bird's liver. Inserting the tip of the hypodermic into the nearly black organ, he exerted a gentle back-pressure and probed with the needle until he was rewarded with a slow spurt of blood. He needed only a single cc-less, actually-but he took the full amount possible, then snapped the sparrow's neck with a quick twist and tossed its carcass into the underbrush.

Opening the petri dish, Dr. Tarver squirted some blood onto the layer of minced chick embryo inside and rubbed it around with a sterile swab taken from his pocket. Then he closed the dish and slipped it into the duffel with the Ziploc bags. His gloves came off with a snap-those went into the bag, as well-and then he cleaned his hands with a dab of Purell. A good morning's work. When he got back to the lab, he'd test the last bird first. He felt confident that it was a carrier.

A slow shiver in the grass where he'd tossed the sparrow raised the hair on his arms. The accompanying sound was faint, but the sounds of childhood never faded. Dr. Tarver set down the Nike bag and walked lightly-very lightly, considering his size-toward the closing groove in the grass. As soon as he saw the rotting log, he knew. He closed his eyes for a moment, stilling himself at the center. Then he reached down with his left hand and lifted the log. What he saw beneath fluttered his heart: no crotalid, but a beautiful coil of red, yellow, and black shimmering in the sun.

"Micrurus fulvius fulvius," he whispered.

He had uncovered an eastern coral snake, one of the shiest serpents in America, and undoubtedly the deadliest. With a fluid motion like that of a father stroking his child's hair, Tarver took hold of the stirring elapid behind its head and lifted it into the air. The brightly banded body coiled around his forearm-a full twenty inches of him-but this was not a strong snake. A cottonmouth or rattler would have struggled, using its strong muscles to try to whip away from him and strike. But the coral snake was no brutish pit viper, injecting prey with crude hemotoxin that caused terrible pain and swelling as it ate away the walls of blood vessels, bringing gangrene and infection to its human victims. No, the coral was a refined killer. Like its relative the cobra, it injected pure neurotoxin, which brought only numbness before shutting down the central nervous system of its prey, quickly bringing on paralysis and death.

Dr. Tarver was a pathologist, not a herpetologist, but he had a long history with snakes. It had begun in childhood, this education, and not by choice. For Dr. Tarver, serpents were inevitably bound up with the idea of God. Not the way his adoptive parents had seen this relationship-because only fools tempted death as a test of faith-but bound up with God nonetheless. As a boy Eldon had watched dozens of frightened rattlesnakes held high by chanting hillbillies who believed that God had anointed them against the lethal compounds in the bulging poison sacs behind the slitted eyes. He knew better. He had seen many of those hillbillies bitten on their hands, arms, necks, and faces, and every blessed one had suffered fleshly torments beyond their imagination. Some had lost digits, others limbs, and two had lost their lives. Eldon knew their fates because he had been one of those hillbillies once, not by choice or even by birth but by the authority of the State of Tennessee. He also knew that the skeptics who accused his adoptive father of keeping the snakes in refrigerators to make them sluggish, or of milking their venom before the services, had no idea whom they were talking about. The faith of those hillbillies was as genuine as the rocks they plowed from the brick-hard earth of the Appalachian foothills every day but Sunday. They wanted death in the church with them when they witnessed to the Lord. Eldon had personally gathered many of the vipers for Sunday and Wednesday services. The church elders had quickly seen that the big, birth-marked boy taken from the Presbyterian Children's Home in Knoxville had the gift-so much so that his adoptive father had begged him to take up the cloth himself. But that was another story…