The Alien Apocalypse
Elizabeth remembered the day everything was normal, grass was green, sky was blue, children were happy, until a certain day aliens were discovered.
The Aliens and the humans both thought they were the only species in the universe, until now. The Aliens' planet is dying because they've used up so much of their planet's resources to produce the advanced technology they survive on. When they find Earth, they start out with a simple warning, the first stage.
They want to make peace through their language. The Aliens agree to equally share the planet. Since humans had no idea how to interpret the language, the Aliens took that as a no. They took it as war.
The second stage is the take over, when they bring in all their life forms to settle into their new home, bringing their controlling devices into play, the worms. They use this to bring the humans into desperation, and also for extra help.
The third stage is the annihilation of the human race. Do they fail? Or do they succeed?
PS: Inspiration for this story is 'Falling Skies' the tv show, and 'Signs', the movie. It's part fan-fic in the beginning, but I've grown it to be a little more different near the end and starting in the sequel when I begin writing it.