Captain William Roberts is a member of military intelligence dispatched on duty at Area 51. His duties of guarding the highly top secret base are compromised when an alien craft crashes a mile away from the base. A day after the aircraft is retrieved, a militaristic alien force quickly overwhelms the base, seizing control of the base and resurrecting its personel for their own use. William and a few other soldiers are the only survivors.
Private First Class Richard Johnson is a newly joined member of the Alien Tactical Xtreme Defense Force (A.T.X.D.) whose is tasked with fellow soldiers Stephanie Miller and Marcus Conner to team up with the survivors of the Area 51 massacre and take back the military installation. Little does Richard know, he will learn that there is more behind this enemy's motives than just a takeover. Richard and his team will also uncover sinister and mysterious secrets hidden away inside the base's underground containment facility, codenamed Stronghold Beta.