In the year 2019, star ships of unknown origin started to orbit Earth. As much as the nations of the world tried, contact could not be made. Then, one day, millions of pods came crashing down from the ships. They struck everywhere, New York, Beijing, Dubai, Paris, London, Frankfurt, Rome. They would crash to the earth with an explosion, seemingly just a giant chunk of metal. But before scientists could arrive to inspect it.
They opened. And in them contained a small scaly life-form with a giant pack on it's back. This life-form would leap out and flee the scene at an impossibly fast speed, disappearing. Little did we know, that these creatures would be the first building block in this godforsaken war. They were caretakers, teachers, "Brothers" if you will. They raised soldiers to adult age in less than 6 months right under our noses. And while we tried to pick apart their pods and futilely attempt contact, they attacked. It was organized, it was viscous, and it was effective. Hundreds of thousands died in the initial attack and it would be nearly 2 months before Humanity could organize a counter attack.
But, if nothing else can be said about Humanity, we can pack a hell of a punch.
...
It has been 20 years since the start of "The War for Earth" and Humanity is finally turning the tide. A good portion of the world is in ruin and cities such as Dubai are a wasteland of radiation and death. But there are still hundreds of thousands of strongholds throughout the world, all flying under the banner of the Systems Republic. And recent breakthroughs and technology has put the Republic on a level playing field with The Invaders as far as space travel goes. But that's all the information the republic has given the public. You are a Combat Pararescue Soldier [CPJ] with the Republic Airforce. You are flown into the shit to pull wounded soldiers out. CPJs are regarded as some of the greatest assets of the Republic Military, saving countless servicemen and women. The Invaders seem to be getting desperate their attacking more viciously and sporadically. Of course this makes your job harder, but it's a sign of progress. And only time will tell if there is Hope on the Horizon.
[I will of course add more info if there is sufficient interest.]