In a quiet suburb of San Francisco, something strange is happening. Daily life is interrupted when residents begin to notice that their friends and family are acting very oddly. Dr. Miles Bennell, a local physician, returns from a trip and learns that several of his patients have reported that their loved ones have changed, as if they are merely shadows of themselves. At first, Miles and his ex-girlfriend Becky believe it might just be people going mad, but as they investigate, they discover that the truth is much more terrifying.
The plot intensifies when Miles and Becky encounter a strange alien life form that has the ability to replicate people, taking their appearances and leaving behind emotionless copies. As paranoia spreads throughout the town, the protagonists try to unravel the mystery and realize that more and more citizens are becoming part of this silent invasion. Friends turn into enemies, and the increasingly limited circle of people Miles can trust shrinks drastically.
With a tense atmosphere and a subtle critique of social conformity, this story becomes a game of survival where no one is who they claim to be. Miles's struggle to maintain his humanity and figure out how to stop the invaders turns into a harrowing race against time.