he plot centers on Dr. Matthew Bennell, a San Francisco health inspector who, with his collegue Elizabeth Driscoll, discovers that people are being replaced by simulations grown from plantlike pods, which produce perfect duplicates with the same memories and thoughts, but without love or affection, whose only instinct is to survive. The pods are able to duplicate humans only when they are asleep, not awake. The human bodies disintegrate after the duplicate is fully formed. At first, Elizabeth's boyfriend, Geoffrey, suddenly becomes distant and she knows something is wrong. Matthew suggests that she see his friend Dr. David Kibner; but they meet people all over the city stating that loved ones are no longer their loved ones.