一个异形在美国流窜，为了得到它想要的，它杀掉所有挡它路的人，并且用他们的身体作为新的藏身之所，它不断追寻的是生命的能量，然而另一个借用了一个死去的FBI探员身体的异形对它紧追不舍，无数无辜的人们在这场追击中丧生
Plot Summary:An alien parasite with the ability to possess human bodies goes on a violent crime spree in L.A. A human cop, detective Tom Beck, and an alien cop posing as a young FBI agent Lloyd Gallagher both pursue the parasite who frequently changes his human hosts.
