One by one, the residents of San Francisco are becoming drone-like shadows of their former selves. As the phenomenon spreads, two Department of Health workers, Matthew (Donald Sutherland) and Elizabeth (Brooke Adams), uncover the horrifying truth: Mysterious pods are cloning humans and destroying the originals! The unworldly invasion grows stronger with each passing minute, hurling Matthew and Elizabeth into a desperate race to save not only their own lives, but the entire human race.