The first remake of the classic paranoid infiltration film relocates the invasion from a tiny community to the city of San Francisco, and begins with Matthew Bennell noticing that some of his colleagues are talking about how their close relatives are different in some way. When they are confronted afterwards, they appear to have changed, as they deny everything or make feeble explanations. As the invaders grow in number, they become more opportunistic, and Bennell, who has already witnessed an attempted "replacement," realizes that he and his comrades must flee or face the same fate. However, who can he rely on for assistance and who has already been snatched?