The year is 2254. Humanity has expanded into our solar system - colonizing the moon, Mars, Phobos, Deimos, and several asteroids. We have space stations and secret military bases. But we've spread too far, too fast, and the military cannot adequately police the solar system. Many hopeful colonists are preyed upon by pirates who take what they can with little opposition.

Fireteam Zulu is a group of ex-marines who band together to help those people, hunting down pirates wherever they can find them. Then one day they discover that they are being hunted.