Jason didn't understand most of what his parents told him, except the part where he should never go near the canyon where the mists came out. "Never ever go near there," his father said. "If you fall in we wouldn't be able to get you out." He told Jason there were monsters down there, and that if the fall didn't kill him, the monsters certainly would.
     Jason had seen the canyon twice, once when the worker robots were building the fence, and once after the fence had been torn down. Everyone seemed upset that the fence had been wrecked. It happened during the night, and there were large claw marks in the brown dirt all around the twisted metal. Jason's father said that whatever had done it was very strong, and probably very large.
     The canyon cut across the brown landscape, running from the distant hills all the way to the sea, passing the edge of the settlement on the East side. The settlement had been placed beside the canyon because of the mists. Jason's computer told him that the mist was made up of tiny droplets of water, and this water helped the settlement's plants grow.
     The plants were everywhere, surrounding Jason's home and lining the roads and filling every little spot in between. "Earth plants," they were called. "From the homeworld." Jason liked to walk among them, especially the trees, and wonder what it was like to be on Earth.
     The other kids were usually out playing among the trees, or out at the edge where the robots were doing the new planting. Bradley Rosewald was there, as was Frederick Turney and his sister Stephanie. They were the three that were of about Jason's age. Stephanie, who was tanned and dark-haired like her brother, was pinching her nose in distaste. "It smells here," she complained. "That stuff is pooo-cheee."
     "Dad says it smells a lot worse when they pull it out of the ocean," Frederick said. "Before they take the salt out of it."
     "Why do they have to put it in the ground?" Jason asked, watching as a large autonomic tractor laced the soil with the green, odorous slime.
     "It gives the plants something to eat," Bradley Rosewald said.
     "To eat?"
     "Of course. Don't you know anything, Jason? This soil is sterile, it has no nutrients in it."
     "Oh." Jason decided he'd ask his computer what "nutrients" were when he got home. "How did the soil get sterile?"
     Bradley rolled his eyes. He was the oldest of the four, with bright blond hair and a freckled face. His eyes were a shining blue. "What a question," he said, and didn't bother to answer.
     As they watched the robotic equipment toiling in the endless brown dirt, a mist drifted in from the East, mingling with the plants and blocking the sunlight. The temperature dropped a bit and Jason felt his jacket warm up to compensate. He still felt a chill, though --- he knew perfectly well where the mist was coming from.
     "Hey," Bradley said. "Let's go peek over the edge."
     Frederick was all for it. "Yeah, let's see if we can see the monsters." He and Bradley stood up, and took several steps toward the East. Stephanie stood up, looking unsure. Jason was transfixed with horror.
     The two boys stopped, turning around. "You coming?" Bradley said.
     "I can't go there!" Jason said. "My parents told me never to go there!"
     "We've been there thousands of times," Frederick said. "There's nothing to it."
     "We throw rocks down there," Stephanie said. Her voice was quiet, her eyes on Jason. "You won't tell, will you?"
     "You throw rocks?"
     "Yeah," Frederick said. "Once we heard this long, mean growl. Grrrrrrr! Like that."
     "What's wrong? You're too precious to your mommy and daddy? You're so special 'cause you 'naturally born?'" Bradley was laying the sarcasm on thick. "I think you're afraid. You're afraid 'cause you're still experiencing your birth trauma."
     "I am not!"
     "You are too. Natural babies have birth trauma, that's why they're cowards. Dittos like us aren't afraid of anything." Bradley turned away. "Come on, Frederick."
     Frederick motioned for his sister to follow, then turned and walked off after Bradley. Stephanie looked after them, then turned back to Jason. "Please don't tell."
     "I'm not afraid," Jason lied. "It's just that my parents told me never to go there."
     "Me too." She gave him a deep, meaningful look which Jason didn't understand, then turned and trotted to catch up to the others. Jason saw her fading into the mist and his feet took on a life of their own, one foot stepping in front of the other, carrying him after her even as the rest of him yearned for the safety of home.
     There were pine trees, there were walnut trees. There were apple trees. There was a field of corn. He caught up to them and followed without a word, staring at Stephanie's back and the strands of her hair as it bounced with each step. They came to a clearing and the mist grew thick as paste. This was as close as he'd ever been; about fifty meters beyond was a edge that dropped down into mystery and nightmares. The last time he was here it had been with his father, and that had been scary enough.
     They walked about a half dozen meters through the mist and then Bradley motioned for them to stop. "Listen," he whispered, and was still. Jason listened, expecting to hear a monster's growl. Instead he heard a low rumbling sound, a noise so deep and hard that it seemed to come up from the ground itself.
     "It's louder this time," Frederick whispered.
     "What is it?" Jason asked. "Is it the monster?"
     "No, you dunce. It's water."
     "Water?"
     "Of course, water. There's a river down there. Don't you know anything?"
     All Jason knew about the canyon was that he was supposed to stay away from it. But it stood to reason that if water mist came drifting out of it, then there must be water down there.
     "The water's warm," Frederick said. "It goes through a place where the ground is really hot. My father took me there once, because he works in the power plant up in the hills."
     "It's geothermal," Stephanie said. She pronounced the word very carefully.
     They continued deeper into the mist, and the rumbling of the water grew much louder. When they came across the ruins of the fence, Jason knew they were a mere meter or two from the edge. He was so scared he was shaking, but he was determined not to show it.
     The ground under their feet was soft and wet from the heavy mist. Frederick dug a porous rock out of the mud and tossed it out into the void. That was the end of it --- it simply vanished. They listened to hear if a monster growled, but there was only the rumble of the water.
     Bradley bravely made his way over the bent posts and strewn metal cables of the fence and to the edge itself. He crouched there, peering over. The mist was so thick that Jason could barely see him, and occasional drifts made him disappear altogether. After a moment, Frederick joined him.
     "This is crazy," Jason whispered. Stephanie, who was standing very close to him, said nothing. He felt her hand suddenly grab his, and she took a few steps forward. He followed, each step a thing of torture. At any moment he expected some horrible creature to leap out at them from the mist, something with red eyes, gaping mouth and razor sharp claws.
     On the other side of the ruined fence was a large, damp rock and just beyond a section of ground that had sunk down a half meter. Two meters beyond that was the edge. Jason and Stephanie sat down on the rock, their feet on the sunken shelf, and threw pebbles into the canyon.
     "My dad's computer has pictures of plants and stuff from down there," Frederick said. "They're native plants, way different from the trees."
     "Primitive," Stephanie said. "Dad says they're just learning to come out of the water."
     "They're all gooey looking, like jelly. The leaves are black."
     "My dad has pictures of them too," Bradley said, making it sound like it was all old news to him. "He's got pictures of some of the monsters, too."
     "The big ones?" Frederick said. "With the long teeth?"
     "Yeah."
     "Mean looking?"
     "Yeah."
     Jason seized upon an idea that would get them away from the canyon. "I've never seen pictures of the monsters," he said. "My mom told me they would only give me nightmares."
     "What a baby," Bradley said.
     "I'd like to see them. Can we go look at them?" Jason heard the pleading tone in his own voice, and knew his reasoning was obvious. He was surprised when Bradley missed the opportunity to insult him. Instead, Bradley backed away from the edge and stood up.
     "Yeah, okay," he said. There was a hint of relief in his voice, like he too had been waiting for an excuse to get away from the canyon.
     Their feet still on the sunken shelf of dirt, Jason and Stephanie stood up. When they did, Jason felt the ground begin to sink away from him. For a split second he had a chance to turn and leap away, but he saw Stephanie lose her balance and fall forward. He tried to grab her, and in doing so lost his chance.
     Jason remembered hearing Bradley and Frederick's yells receding above, and the feeling of falling. He and Stephanie were still on a flat section of ground but that ground was sliding down into the canyon. The falling sensation ended for a moment and then he was face-first in the mud, and still they were sliding. The only thought going through his mind was a kind of wonder, thinking with certainty that he was now going to die.
     It seemed to go on and on. Jason had plenty of time to reflect on what was happening. The section of dirt slowed a bit and hit something, which split it into sections and made it disintegrate. Still they continued downward, rolling now, mingling with the damp soil. They crashed through some dark, slippery branches and plunged tumbling into warm water.
     Dirt was still coming down on top of Jason while he was underwater, but then the current carried him away from the slide. He was thrashing and kicking, not knowing which way was up, not knowing how to swim. Never in his life had Jason been in water deeper than a bathtub. He had no idea what to do.
     His knees scraped rock and he pushed up, breaking surface. He gasped for breath and looked around in terror. He could see clearly --- the mist was above him. It hung like a ceiling several meters over the water, and below that the air was crystal clear. He could see black plants, water, and boulders. He grabbed desperately at the boulder near him before the current could pull him away, and crawled on top of it. It was rounded and smooth, very unlike the porous and abrasive rocks he was used to --- it stuck out like a little island about seven meters from the West bank. Jason sat, hugging his knees, not knowing what to do. He couldn't believe he was still alive.
     Then he realized he was alone. "Stephanie!" he shouted.
     A ghostly imitation of his voice called back: ". . . Stephanie . . . Stephanie . . . Stephanie . . ." It was his echo, but he'd never heard one before. It scared him and kept him silent, thinking that the monsters were mimicking him. Indeed, far across the water, near the opposite bank, Jason could see long dark shapes moving against the current. The sight made him shudder, and he remembered what his father had told him: "If the fall into the canyon doesn't kill you, the monsters certainly will."
     He looked around frantically, wanting to get away from the water and up onto the bank. It didn't look possible, as the rocks didn't lead to it, and the water looked deep. He glanced back toward where he'd fallen in, and only saw dark rubbery plants. Despite his fears, he called out Stephanie's name once again. Again the echoes came back to haunt him. There was no reply, and she was nowhere in sight.
     There was a loud splash, and Jason turned to see a long black figure in the water next to the rock. Five times as long as Jason was tall, it slid through the water with an eerie undulating movement, two bulging eyes protruding from the water each the size of a grown man's fist. The eyes were black on black, with no hint of pupil. It came edging against the current toward the rock where Jason was huddled. Jason screamed and leaped headlong away from it, jumping as far as he could toward shore. He floundered in the water, splashing, keeping his head above the surface. The current helped, carrying him closer. He managed to catch hold of a rubbery plant and pull himself to the bank, scrambling out of the water. Tiny, multi-legged animals skittered away from him, and a couple odd-looking things with spring-loaded tails launched themselves into the air. The gooey mud and the plants smelled horrible, but Jason scrambled through them without a thought. It was all a desperate tangle until he stumbled into what looked like a pathway made by something very large. There were thousands of huge claw marks in the mud at his feet.
     Jason called out once again for Stephanie, and followed the path back toward the place they'd come sliding down the canyon wall. It was easy enough to find. The plants were all torn up and half buried, the path wiped out entirely. Jason searched through the mud and the plants and looked out across the river, but saw no sign of her. He turned around and headed downstream, hoping to find her there.
     Every once in a while he called out her name, learning to ignore the ghostly echoes that followed. The path led up and away from the river, up into the mist. The mist slowed him down. At one point the path widened and he stopped, peering through the swirling white. The path split and lead two ways, one heading down to the water, one up toward the canyon wall. Jason chose the path that lead toward the water.
     The rush of the water grew particularly loud, but above it Jason heard something odd. It was a high, hard snorting sound. He stopped, turning around and staring through the mist. It was there, a looming shadow in the path, a huge head on a long thin neck with thick, whisker-like feelers. The body stretched out into the mists and disappeared, too big to see all at once.
     Snorting air through nostrils at the top of its head, it moved forward, feelers tapping at the ground and waving in the air in front of it. Jason gave off one startled yell and ran headlong down the path toward the river. At one point he stumbled and fell in the mud, and while scrambling to his feet chanced a look behind him. The creature was following, waving the feelers blindly in front of itself. Jason had a sudden inspiration and jumped headlong through the plants, away from the path, and up against a large rounded boulder. Pressing against the boulder he waited, hardly daring to breathe. He could see the beast through the tangle of glistening black branches. It continued on past, waving its feelers and moving along with a bobbing motion, it's serpentine body going on and on. The legs were thick but short, and Jason saw the long, bony claws that had made all the tracks. Each claw was as big as his arm. By the time the body was past, he had counted five pairs of legs. The tail was held up in the air, away from the ground, and had a long ridged fin.
     After it had passed, Jason cautiously made his way back out to the path and followed along behind it, ready to turn and run if the beast stopped. His fear had diminished considerably, as he thought of the creature as stupid and probably blind. It was big, though, and that made him feel comfortable. He couldn't imagine anything attacking it. Walking behind the big dumb creature was probably the safest place he could be.
     As Jason neared the river he passed below the mist line, and for the first time he saw the whole creature at once. The sight chilled him. It was twice as big as his house.
     The monster walked in its serpentine way down to shore and plunged into the water, disappearing under the surface. Jason stood as close as he dared to the spot it had gone in, then realized he was out in the open, and turned to walk back toward the foliage. His foot caught on something and he tripped, and as he stood back up he looked to see what had tripped him. It was a metal cable, half-buried in the mud.
     He stared at it, concentrating. It was part of the fence. It looked like one of the creatures had gotten tangled in it and pulled it down into the canyon. Jason followed it with his eyes down to the water, saw it had been haphazardly strewn about here and there, then saw something that made him shout. Stephanie was out in the river, clinging to the fence.
     Jumping into the warm, dark water, he pulled himself along the fence out to where she was. The nearer he got to her, however, the less he liked what he saw. Only an arm and a leg were out of the water, and as he reached her he realized she wasn't clinging to the fence at all. The current was holding her pressed up against it. Jason grabbed her arm and pulled her head out of the water, grimacing as it lolled about, liquid dripping out of her open mouth and nose. "Stephanie?" he said.
     Her skin was still warm from the water, but the color was too pale. She wasn't breathing.
     "I'll get you back up, Stephanie," Jason whispered. "They'll fix you." Still holding her arm, he pulled her toward shore using the mangled fence as a lifeline. As he did he realized that the fence not only led to shore, but up the side of the canyon itself. He could see it, a trail of smashed plants along the shore and a line tracing up the canyon wall and into the mists above. Jason hadn't even dared to hope of finding a way up, but there it was.
     He managed to pull Stephanie up onto the shore, and lay her on her back. Her eyes were half open, and it seemed like she was looking at him, but she wouldn't move. "You're just scared," he whispered. "You saw the monsters, and . . ." He didn't finish. Watching her eyes, he moved his head back and forth but her blank gaze didn't follow.
     A dark, sad thought kept coming to him, but he pushed it away. He desperately pretended it wasn't there. Standing up, he looked carefully at the track of twisted fence. On his own he could probably make his way straight up to the wall of the canyon, but carrying Stephanie? No. It was too much a tangled mess, with cables and rubbery branches wrapped around and strewn here and there. Jason bent down and tried to pick Stephanie up in his arms, but her body was so limp it made it hard. He ended up dragging her along the claw-marked path, making it as far as the junction before seeing another one of the monsters.
     This one was smaller than the first, but seemed more alert. It came down the path from the canyon wall waving its feelers and snorting. Jason saw eyes that looked like black glass imbedded in its head. They seemed to be staring at him, and he gasped in fear and dragged Stephanie back to the spot where he'd hidden from the other one, pulling her through the branches and up against the boulder. The snorting sound followed him, and he saw the feelers enter the tangle of branches and the head poke its way through.
     He pulled Stephanie around the rock and beyond, pushing deeper into the tangle. The beast followed, reaching the boulder and pushing it out of the way. The boulder rolled up onto one side and tottered. Jason, struggling to pull the both of them through the tangle of rubbery plants, felt something hit him lightly on the leg and then on his shoulder. He looked up and saw feelers wavering around his head and a large mouth slightly open, easily big enough to swallow both Stephanie and himself at the same time. "Go away!" Jason shouted at the thing. "Leave us alone!" He swung angrily at the feelers, and managed to connect.
     At the same time, the teetering boulder lost its balance and rolled over, landing on one of the creature's feet. The creature snorted once, then reared up with a loud, huffing grunt, turning back to attack the boulder. Jason watched with a sense of satisfaction, thinking he had scared it off. He heaved a sigh and turned around, then took a hold of Stephanie and resumed pulling her through the tangle.
     He found the fence and was able to follow it to the canyon wall. The mist was thick up here, but through it he could see large holes dug into the sandstone and claw marks going straight up the wall. The fence, twisted as it was, made a good ladder, but Jason couldn't climb and hold onto Stephanie at the same time. He stood with her body crumpled at his feet, wondering what to do. Somewhere in the foliage behind him he could hear one of the beasts crashing around.
     Finally Jason pulled Stephanie's jacket off of her and used the sleeves to make a sling. He looped it under her arms and over his, then managed to get to his feet. He was wearing Stephanie like a backpack, but it was a heavy backpack. Taking one more determined breath, he started climbing up the twisted, fallen fence.
     The crashing and snorting sounds of the beast came closer. Jason paused in his climbing and looked around, but he could see nothing through the mist. He resumed his climb, going slowly, making sure of his grip. His burden was heavy, and it wasn't long before he began wondering just how far he'd be able to climb before he gave in to exhaustion.
     The snorting sound was right below him. Jason looked down and saw a shadow in the mist, and feelers tapping at the wall just under his feet. It motivated him to climb another several meters, but then he had to stop and hang on. His breath just couldn't come fast enough, and Stephanie felt twice as heavy. She was pulling him down, trying to make him fall. Jason was starting to get angry about it. Why did she have to go to the canyon? he thought. Why did she make me follow her?
     Jason realized he was wasting his strength trying to carry her up the wall. He had to face it, she was dead. She had drowned in the river and there was nothing he could do about it. Hanging there in the mist, he began to cry. He felt so hopeless.
     Then the fence moved. The cables in his hands tightened and gave off a peculiar twang, and he and the fence slid down and over a meter. The monster was still below, and it was climbing after him.
     From above, he heard voices. Distant, grown-up voices. "There's something climbing up the fence," a man's voice shouted. "Another one of those damn things is coming up here!"
     Jason yelled out for help as loud as his tired lungs could muster, then he hung there, panting. Once again, he felt the rude tapping of a feeler on his leg, and in annoyance and spite he gave it a kick. The monster gave off a fierce snort.
     "Heeeeeelllpppp!" Jason yelled. He tried climbing some, but couldn't. It took all the effort he had left just to hang on.
     "There's a kid down there!" someone from above was shouting. "One of the kids is down there!" He heard scrambling sounds, like boots sliding on dirt, and little rocks came tumbling down on him. "Hang on, kid!" the man's voice yelled. Another, more distant voice shouted: "We found the kids!"
     The monster's head lunged upwards, huge claws raking at the canyon wall. The feelers were all over Jason now, tapping, prodding. The head moved slowly up and back, nose coming down, so that the mouth was level with Jason's shoulders. Claws sunk into the sandstone to either side of him. The snorting sounds were very loud, and close together, like the creature was excited.
     "Hang on, kid!" came the call again from above. Jason could feel vibrations in the cables, like there was someone making his way leisurely down toward him. The feelers were slapping up against him so hard they were nearly knocking him off. He saw the gaping mouth opening and the long, sharp-looking teeth a meter away, and he couldn't climb up. Instead, he began climbing down.
     The creature leaned forward to bite, but its nose hit the sandstone a half-meter above Jason's head. It snorted and pulled back. Jason climbed down another few meters. The creature moved its head back and forth in frustration, unable to bend its neck down far enough to reach him.
     Jason heard more yelling from above, but couldn't make sense of the frantic words. He kept looking at the huge mass of the beast's grey-green belly an arm-length away. There was a horrible scraping sound as the beast's claws slid over the sandstone --- it was lowering its body so that it could reach him. Jason climbed down further.
     "Kid!" a voice yelled. "Kid, keep as close to the cliff as you can!" After a moment, there was a series of hard, loud concussions. Claws raked past Jason, digging deep furrows into the cliff wall. When the beast's head passed it snorted a spray of cold, sticky blood. It fell away into the mist. There was a loud crash below, then angry thrashing. Looking up, Jason could see a pair of boots descending toward him. In a moment he saw the man's face, and recognized him as one of his neighbors. Hanging from his shoulder by a strap was a smoking rifle.
     "Are you okay?" he asked.
     It took a moment for Jason to answer. "I can't climb anymore," he finally said, his voice full of shame. "She's too heavy."
     The man eyed Jason and then his burden. His face creased in pain, but he forced a smile. "You made it this far. That's pretty damn good if you ask me."
     With the man's help, and the help of others who came down from above, Jason made it out of the canyon and into his mother's arms. She hugged him eagerly, but he only felt numb. He kept glancing over at Stephanie's family, feeling pains of guilt and remorse. They were very silent and when they left, Stephanie's father was carrying her, tears streaking his face.
     "Thank God," his mother was whispering. She was hugging him and rocking him back and forth like he was a baby. "Thank God it was her and not you. Thank God." She was crying.
     During the months that followed, Jason's parents hardly let him out of their sight, let alone out of the yard. Bradley and Frederick occasionally came by to see him, but they were distant and very subdued. Jason thought it was because of what happened to Stephanie, but later began to realize it was something else. It had something to do with what Jason's father had told him, that Bradley, Frederick and Stephanie were Dittos and Jason was the real thing, a natural child. The other children were "replaceable" and Jason was not.
     It was almost nine months to the day when he heard Stephanie was alive again. Her mother and father brought her over so that Jason could see her, because they said he was a hero for trying so hard to bring her out of the canyon. He was perplexed when they held out a tiny bundle of blankets. Jason held her in his arms, a tiny little figure with no hair and stubby arms and legs. He could see a little of Stephanie in the baby's face, but that was all. When they left, he tugged on his mother's sleeve and said, "That wasn't Stephanie."
     "Yes it was, Jason. It's just that she's younger than she was."
     He didn't believe her. He couldn't. Even when he was older and understood the concept, she still wasn't the same person to him. She grew to look just like the Stephanie he knew; she acted the same, talked the same . . . but she didn't look at him the same.
     Over the years the colony's forests and farmlands spread past the horizon, and thousands upon thousands of new people came there to live and work. Jason, as a man, often walked to the canyon's edge and stared into the mists, throwing rocks and --- sometimes --- even calling out Stephanie's name. When the ghostly echoes came back he liked to imagine it was her spirit drifting in the mist, answering. During these times he would leave the canyon feeling a little better, a little lighter, as if she had reached out through the mist and touched him.