"The aliens don't exist," Sarah said, a frown on her face. She glared at Justin.

"Sure they do," Justin said. "Can't you see them?"

Sarah didn't say anything, just continued to glare.

"Oh, I get it. They don't exist! They're just figments of our imaginations, right?"

Without a word, Sarah turned and left the room. Justin could hear the door slamming upstairs.

He put down his cup of coffee and stepped outside. The green layer of slime that the aliens had brought filled up the sky, a translucent sheet of muck. He couldn't see any blue in the sky at all, just the murky green.

The aliens don't exist.

And then a thought came to him. What if they didn't really exist after all? What if it was just a bunch of nonsense? What if the government had just released a bunch of nanopollutants into the atmosphere to make it green and called it an alien invasion?

In fact, Justin thought, what aliens? The green slime itself? There weren't any aliens.

When the layer of slime had first appeared, President Cornwall had gone on TV and explained calmly that the slime was a weapon by which the aliens meant to enslave the human population of Earth. Do what they said, she said, or Earth will be zapped into oblivion.

It sounded like some junk out of a sci-fi B-movie. Who would ever have guessed it would actually happen? Aliens!

But what Sarah said was beginning to make sense. The government was enslaving the population, and concocting a nonexistent alien invasion out of nowhere to get people to do what it wanted.

Silently, he got up and went back inside. Through the window, he could still see the green slime. It wouldn't go away--not for a while.