Walker steered the rowboat into the center of the lake, and then for several minutes the three of them watched the creatures they’d left behind.

Most of the dozens now collected there stopped at the water’s edge, but some moved into the lake in pursuit, their eyes focused on Walker and his family. Only a few of these engaged in anything resembling swimming, looking as if their arms vaguely remembered something that the rest of their body had forgotten. But they too, like all of the ones who’d entered the lake, eventually slipped under the surface and did not reemerge.

“What’s going on?” Ryan asked.

This was not Walker’s son, the boy who knew everything, or who could at least make up a passable answer. This boy was that boy’s shell.

“I don’t know,” Walker said. It was an admission of ignorance, but in a tone that said that whatever was going on, he would deal with it. He wanted his son to believe that the situation, while seemingly out of control, was still in Walker’s grasp.

Walker looked across the lake at the creatures still standing on the shore, the ones who’d refused to enter the water. What were they thinking? What had kept them out of the water? Was it ‘thinking’ it all? Or just pure instinct?

It was a small, tear-shaped lake, tucked into the foothills of the alps. The cabin they’d just abandoned was on the flattest, widest edge, surrounded by forest. At their backs, across the lake from the cabin, was a tall bluff — an impassable wall of rock. If they were going to land the rowboat somewhere, it would have to be at one of the ends. The teardrop end, tucked out of view of the cabin, made the most sense. Walker began to row.

As they entered the teardrop, the cabin about to slip out of view, Walker saw some of the creatures collected there start to move along the shore in their direction. But he was not worried. Walking along the lake’s edge to where they would land would take them at least half an hour. By then, Walker and his family would be gone.

The teardrop was narrow and surrounded by trees. They were high up, at least three thousand feet, but still below the tree line. After scanning the shore, searching for any sign of movement and finding none, Walker brought the boat in against a large flat rock that jutted out into the water, like a natural dock.

“Everybody out,” he said.

Ryan was the first one up onto the rock, his small pack on his back. Jane, still tired and hungover, yet bearing an edgy alertness, followed him up.

“What’s happening, Mom?” Ryan asked.

“I’m sure we’ll be okay,” she promised, taking him abruptly into her arms.

“Do you know why we’re here?” Ryan asked.

“We’re on vacation,” Jane said. “We needed a break, time away as a family.”

Ryan had heard all this before, and it still didn’t sound convincing. They had taken him out of school in the middle of the spring. Mom had walked away from her job. Dad had left his store in the hands of a nineteen-year-old college sophomore. And then there were the other things that had happened at around the same time, things that had left Ryan feeling sick and confused.

Standing on the rock, reaching down, Walker pulled the boat in and tucked it into some shrubs growing where the rock met the shore. The boat wouldn’t stay there, Ryan knew, but his father didn’t seem to care. It was a perfunctory act. They wouldn’t be coming back this way. They wouldn’t need the boat again.

“It doesn’t make sense,” Ryan told his mother.

“I know,” Jane admitted. “I’m sorry, honey. It’s all my fault.”

Walker was now standing over them, arms akimbo, peering up into the woods. He looked both heroic and menacing.

“Do you see a trail?” he asked.

Jane and Ryan were sitting with their backs to the forest. Turning their heads, they could see nothing but a gentle slope of bushes and trees, with no sign of a clear way through them.

“We need to find a trail,” Walker said when no one answered. “They’re well marked. There’ll be signs, with place names.”

“What about the trail we came in on?” Jane asked.

“It’s on the other end of the lake.” Walker said. “We’re not going back that way.”

“Didn’t it run across that ridge–?”

Jane abruptly stopped speaking, her eyes on the wall of rock. Seeing the sudden look of fear in her eyes, Walker and Ryan followed her gaze. A figure was moving along the bluff toward them, slowly, in a lurching stroll that was unmistakable. It was one of them, whatever they were, and it was headed in their direction. Then behind the first figure, a second appeared, followed by a third.

“It’s time to move,” Walker said, reaching down and grabbing his wife’s upper arm, lifting her. “Get up, Ryan.”

“What are they, Dad?” Ryan asked as his father nudged him off the rock and into the woods.

“I don’t know,” Walker said. “Something’s happened up here. Something’s gone wrong.”

“Are they sick?” Ryan asked.

“At the very least,” Walker said. “Let’s just get back to Bern and let the Swiss figure it out.”

***

They pushed through the trees until they found a narrow trail at the bottom of the bluff. It ascended from the lake at an easy angle, leading up to their left. They followed it until they arrived at the point where the bluff ended, and a large, open expanse greeted them.

Before them was a wide valley stretching downward to the west. At the far end, Walker thought he saw buildings — not a village, but a city. Perhaps it was Bern, but even on such a clear day, with an unobstructed view, he couldn’t be sure. The distance was too great.

Jane and Ryan were waiting for his instructions. Walker looked up the bluff toward where they’d seen the three figures, but they were still down the other side and moving slowly. If they found cover quickly, perhaps they’d be out of sight before the creatures reached the top.

Looking down at the trail, Walker saw that they were at an intersection. One branch led up the bluff toward the creatures. Another arced down and around the end of the lake, seemingly back to the cabin. A third snaked down into the valley, eventually disappearing into a long patch of forest several hundred yards away that clung to the south side of the valley. This path was their only option.

Walker pointed to the trees.

“Let’s go,” he said.

***

Ryan’s pack was small but heavy. He had, as usual, brought along too many books.

The single volume he’d snatched up from his desk as his father had rushed him out of the house had been consumed by the time they were halfway across the Atlantic. As usual, it had been nonfiction, a book with a long title about the genocide in Rwanda that he’d been unable to put down. For the rest of the flight, five or six long hours, he’d tried to occupy himself with the plane’s entertainment offerings. But the movies and TV shows had been dull and predictable, manipulative fabrications that had left him cold.

In the Zurich airport, they’d stopped for supplies, and Ryan had insisted on visiting the bookstore, where with his recent deprivation in mind he’d gone overboard. There were six books in his pack right now; two others, one of which he’d not quite finished, were back in the cabin on the nightstand in the bedroom he’d been sleeping in for the last two weeks. Whatever else was in his backpack was whatever had been inside when Walker had tossed it out into the hall. Perhaps a change of clothes. Perhaps the sneakers he hadn’t worn since Zurich. Definitely not his toothbrush, but they could replace that once they arrived in Bern.

Entering the forest, Walker in front, Jane in back, Ryan in the middle, the massive valley they’d been in disappeared, and the world once again became small. To their left, the forest climbed thickly upward; to their right it was a steep slope down. The people who’d attacked their cabin were now far behind them, and certainly unable to see them. For the first time since he’d been abruptly awakened by the destruction of his bedroom window, Ryan felt safe.

Yet uncertainty still occupied his mind, an uncertainty that had been born the morning Walker had burst into his bedroom two weeks ago and announced that they were leaving. Not only had there been no advance notice, but he’d been taken out of school in the middle of the spring. And there’d been no explanation, other than that it was urgent, necessary, unavoidable. It had even seemed that they’d left too quickly to inform his school. Ryan had packed quickly and thoughtlessly, and they had left for the airport that day.

Do you know why we’re here? Ryan had asked his mother.

We’re on vacation.

No they weren’t, Ryan knew.

The trail turned suddenly to the left and then straightened out again, a detour made necessary by a massive rock that clung to the steep slope. Beyond the rock, a heavy-set man stood, his arms at his side, his fists clenched. His mouth was open, his lips forming a dark purple oval. Again the icy green skin; again the grey, dull eyes. Like the others, he had once been human but wasn’t anymore. Seeing them, he raised his arms and his fingers uncoiled, and he lurched hungrily toward Walker.

Suddenly there were hands on Ryan’s shoulders, turning him around. It was Jane.

“Run!” she yelled, and then she flung him into the forest with a strength he could hardly believe she possessed.

“Run!!”

***

The momentum of his mother’s shove combined with the weight in his pack carried Ryan swiftly down the hill away from the trail. The forest floor was a tangle of low shrubbery that caught at his ankles, threatening to upend him. The trees were narrow and spread far apart. He reached out for one as he passed it, his palm merely scraping across its rough surface.

Up ahead he could see a horizontal gap, a road that had been cut through the forest. As he came crashing down out of the trees, a rogue branch caught the fabric of his rain jacket, jerking him backward and then spinning him around. The jacket tore and the branch released him, and he landed on his back on the road’s hard-packed dirt surface.

He was stunned from the fall, but the fear coursing through his body immediately reminded him of the threat he’d been running from. He quickly regained his feet and peered up into the forest. The man was not there, but Ryan was not surprised. Like the others, he’d been moving slowly. But the hills seemed to be full of these creatures, emerging from out of nowhere. He had speed on his side, but he and his parents were probably outnumbered. It was important, Ryan knew, to stay alert.

Standing in the middle of the road, Ryan concentrated on his breathing, which was harsh and heavy, and which prevented him from clearly hearing the sounds in the dark curtain of trees into which he was staring. He tried taking deeper breaths, filling his lungs to slow his breathing down, and gradually it worked. After a short time, he was immersed in a gentle blanket of ordinary outdoor sounds, and a sense of normalcy overtook him. For a moment he could forget the bizarre and horrific rupture that had just opened up in what had been a normal twelve-year-old American life.

A movement in the trees caught his eye, and Ryan knew that it was not one of his parents, but one of them. It was the way it was walking, slow and indirect, decidedly unhuman. Ryan knew there was no need to flee just yet. When the time came, he would be able to outrun the creature. So he would wait and see. Wait and see if Mom and Dad also emerged from the woods. They would come for him, and if he ran too far, they would never find him, and he would be lost.

When the figure in his sights stepped into a patch of daylight, Ryan saw that it wasn’t the man from the trail. This one was a woman, and she was missing a huge chunk of her body from her left collar bone down to just above her hip. Her ribs seemed to have been pried open, revealing a lung and her heart; her intestines were hanging down to the ground, trailing behind her. Whatever illness this woman had, how on earth was she still standing? Or was it an illness at all?

Then suddenly, a short distance down the road in the opposite direction, the heavy-set man from the trail tumbled out of the forest, tripping on some unseen obstacle and landing bluntly on his face. Ryan still didn’t move. He was terrified, horrified, but reassured by the distance that separated him from them. But what did it mean that the man from the trail was now here? What had happened to his parents?

Ryan shuddered.