Stop and pish. Stop and scan. Back past the truck carcass. Past the buildings. Through the mosquitoes. Despite the repellent, they do land. How many bites will you end up with? You won’t feel them till later.

You see another redpoll, or maybe the same one again. A golden-crowned sparrow is bathing in the creek, fluttering its wings to flip water onto its back.

"Stupid thing." Your daughter is mad at it for not being a bluethroat.

"We tried our best," you say. You remember your wife. Sometimes it just isn’t good enough.

There’s the rental car. You look around one more time. The bluethroats aren’t supposed to be here, so close to the main road. But they aren’t where they’re supposed to be, so what the hell? A bird in the willows… is another American tree sparrow. You don’t need your daughter to identify this one for you.

She sees it, too, and what it is. She shakes her head and lowers her binoculars.

You open the door and quickly slide in. Your daughter does the same thing on the passenger side. You both kill some of the mosquitoes that got in with you. Then you start the car. You turn around carefully on the narrow track. Back toward the road. Back toward Nome.

Maybe, behind you now, the bluethroats flit through the willow branches. Maybe they snatch mosquitoes out of the air and carry them back to hungry hatchlings in their nests. Maybe they were never there at all.

I’ve been interested in ecological invasions and in what people call the Cambrian explosion for a long time. This little piece originally appeared as a "Probability Zero" in Analog. Zero? I don’t know. Have you got a better explanation?

So Many Worlds, So Little Time, said the slightly scorched sticker on the side of the starship

This one had an oxygen atmosphere, but not much else going for it. The oxygen meant there were plants in the seas. The ship’s database said those seas held animals, too: wormy things crawling on the mud, maybe digging into it; blobby things floating in the water. That was about it.

On land? Nothing. Zero. Zip. Zilch. Bare rock. The chewed-up bare rock that’s called dirt. No trees. No flowers. No grass. No ferny things. No mossy things, even. No nothing. Certainly nothing scurrying over the ground or buzzing through the air.

Sometimes planets like this had a stark beauty. The father liked such worlds, which was why they’d stopped at this one. But he’d flitted here, and he’d flitted there, and he had to say he was disappointed.

The mother wasn’t. She hadn’t much wanted to come here in the first place. But they’d been married a long time. If you expected him to give a little, you had to do the same.

They stood side by side, watching the ocean lap against a tropical-but bare, utterly bare-beach. He sighed. "I’ve seen about enough," he said. "It… just isn’t quite what I hoped for."

Told you so. But she didn’t say it. They had been married a long time. All she said was, "I wouldn’t mind seeing something different."

"We’ll do that, then," he said.

He was just turning back toward the ship when the kids swarmed down the ladder and ran toward him. That was a prodigy of sorts. The kids cared more about their games and the aquarium than about seeing what they thought of as a dull old planet. Well, by now he thought of it the same way, which was the problem.

"What’s up?" he asked.

"Aquarium’s in trouble," the girl said.

"Environmental unit crapped out," the boy agreed. He’d head off to the university after they got home. Where did time go?

"Well, plug in the replacement," the father said. They both looked shamefaced. "We forgot to pack one," the girl said.

"Oh, dear," the mother said.

"Without an environmental unit, everything’ll die." By the way the boy looked at the father, it was somehow his fault.

"I like the critters in there. I really like them." The girl sounded heartbroken.

"I don’t know what to tell you." The father knew damn well it wasn’t his fault.

The girl pointed toward the sea that seemed to stretch forever. "Could we… give them a chance, anyway? Not just watch them die?"

"It’s against the rules," the father said doubtfully.

"Please!" the kids chorused.

"I’ll never tell," the mother added. "Who’s to know?" "Well…" He thought a minute, then shrugged. "Okay- go ahead. But keep your mouths shut after we get home, you hear?"

"You’re the greatest, Dad!" the boy said. He and the girl ran back toward the ship.

Jack Conway fired up his Mac and started the Power-Point presentation. A projector put one weird creature after another up on the big screen. "This is a trilobite-an early arthropod. Some of you probably recognize it," Jack told his class. "This is Selkirkia, a priapulid worm. It lived in the mud, as they still do…This is Aysheia, a lobopod. Looks something like a worm and something like a bug, doesn’t it?.. Hallucigenia- great name-is probably another lobopod, with protective spines… Canadia is an annelid, related to earthworms… And this little fishy thing with eyestalks or antennae or whatever they are is Pikaia, an early chordate- -somebody from our own phylum."

He paused. "Nobody quite knows why there was such an explosion of metazoan body plans at the beginning of the Cambrian, 543 million years ago. Some of the more interesting theories include…"

I don’t quite know what you’d call this story. Dark fantasy? Horror? Something in there. Not a place I seem to go very often, but I did this time. The other line that occurs to me is from Marlow: Why this is hell, nor am I out of it.

He woke in darkness, not knowing who he was. The taste of earth filled his mouth.

It shouldn’t have ended this way. He knew that, though he couldn’t say how or why. He couldn’t even say what this way was, not for sure. He just knew it was wrong. He’d always understood about right and wrong, as far back as he could remember.

How far back was that? Why, it was… as far as it was. He didn’t know exactly how far. That seemed wrong, too, but he couldn’t say why.

Darkness lay heavily on him, unpierced, unpierceable. It wasn’t the dark of night, nor even the dark of a closed and shuttered room at midnight. No light had ever come here. No light ever would, or could. Not the darkness of a mineshaft. The darkness of… the tomb?

Realizing he must be dead made a lot of things fall together. A lot, but not enough. As far back as he could remember… He couldn’t remember dying, dammit. Absurdly, that made him angry. Something so important in a man’s life, you’d think he would remember it. But he didn’t, and he didn’t know what he could do about it.

He would have laughed, there in the darkness, if only he could. He hadn’t expected Afterwards to be like this. He didn’t know how he’d expected it to be, but not like this. Again, though, what could he do about it?

I can remember. I can try to remember, anyways. Again, he would have laughed if he could. Why the hell not? I’ve got all the time in the world.

Light. An explosion of light. Afternoon sunshine blasting through the dirty, streaky windshield of the beat-up old Ford station wagon bouncing west down Highway 16 toward Philadelphia.

A bigger explosion of light inside his mind. A name! He had a name! He was Cecil, Cecil Price, Cecil Ray Price. He knew it like… like a man knows his name, that’s how. That time without light, without self? A dream, he told himself. Must have been a dream.

Those were his hands on the wheel, pink and square and hard from years of labor in the fields. He was only twenty-seven, but he’d already done a lifetime’s worth of hard work. It felt like a long lifetime’s worth, too.