在1947年美国军队击落不明飞行物之后，几代精英突击队员被秘密训练，以处理外星人的恐惧报复。 然而，地外部队从来没有回来，精英部队解散。 罗斯威尔失事后六十六年，外星人入侵地球，只有过山顶的退役突击队才能阻止他们。

After the American Army shot down a UFO in 1947, generations of elite commandos were secretly trained to deal with the aliens' feared return. However, the extra-terrestrials never came back and the elite force was disbanded. Sixty-six years after the Roswell crash, the aliens are invading Earth and only the over-the-hill retired commandos can stop them.