What's Going On:
It is 2343 AD. Humanity took to the stars two and a half centuries ago, to escape the death of Earth, and it was then they met aliens for the first time. Nobody had ever imagined that the true First Contact could go so wrong. What had turned out as a misunderstanding between the Americans and the red-skinned amphibians who called themselves the Shoan, escalated into full-on war. It lasts to this day and the humans have all found different ways to deal with it, some seeking to escape it as others embrace it. While some of Earth's 21st century superpowers have managed to maintain their cultural identity, other groups and alliance have been formed as well. Humanity has taken extraordinary leaps in science thanks to reverse-engineering any alien technology they can get their hands on.
One of these is the Path of Peace, a federation of planets brought together by faith, not culture. Their attitude to aliens is the most radical: aliens are the true demons of Hell and must be exterminated from the galaxy in order to bring about the Second Coming. To achieve this goal (which is opposed by some of the more peaceful factions), the organization named the Hand of God was created in 2289 AD. The Hand of God is the federation's secret police and war machine, devoted to acquiring alien technology and resources to use against their enemies.
Belonging to this organization is one of the most prestigious jobs a man can have in the Federation (as it is also called). Each year thousands of hopeful youngsters enter the Battle Academy in order to earn a degree and to be hired. Half don't make it through the application process, and only 1% of those is ever hired.
You got lucky. You are smart, strong, talented and vicious enough not to be destroyed by this job (at least not right away) and they like you. You graduated a week ago, after three years of the most exhaustive training in the entire galaxy. Today is your first day in New Zion, where the Hand's headquarters are situated. What Is Really Going On:
Your character gets partnered with one of the most notorious agents the Hand has, and discovers that the Hand is not as perfect as it claims to be and that mankind is in danger of getting wiped out once and for all.
Now, what I like at the moment is to have two quite dominant characters constantly challenging each other as they go on these missions (killing aliens, stealing stuff, anything we can cook up), and finally maybe even having sex with each other. If they don't get killed first.
Might push Extreme due to the sheer fucked-upness of this world. Really. The humans are completely bigoted towards aliens and in the Federation most of them are also religiously brainwashed.
If you want to know more, just PM me.