Earth is under siege by an alien race. The Strogg are cybernetic warriors--a mechanical frame and decaying body parts stabilized by flesh consumed in a systematic annihilation of other species and civilizations. In a desperate attempt to survive a Strogg attack on Earth, an armada of Earth`s finest warriors is sent to take the battle to the Strogg home planet. Earth`s initial assault force is nearly annihilated immediately, but one marine manages to infiltrate the base, bring down their planetary defense systems, and kill the Strogg`s collective brain and leader--the Makron. Earth assumed the destruction of the Makron would end it all, but it didn`t.

That`s where QUAKE II leaves off and QUAKE 4 begins.

The Strogg are quickly regrouping. However, with the Strogg`s planetary defenses still destroyed, Earth`s forces can deliver a full and final assault. This time, you`re not alone. You are Matthew Kane, an elite member of Rhino Squad, and part of Earth`s next invasion wave. An army of soldiers are fighting with you and an arsenal of weapons and vehicles are at your disposal in this heroic and epic battle between worlds.