Invasion of the Body Snatchers, released 5 February 1956, was based on Jack Finney’s 1954 sci-fi novel The Body Snatchers (originally serialized in Collier’s magazine). To avoid confusion with the 1945 film The Body Snatcher, the title was changed first to They Come from Another World, then run through four different alternatives. The final title was chosen in late 1955. However, it’s still known as Invasion of the Defilers of Tombs in France, due to a mistranslation.
The film opens in a psych ward, where a hysterical Dr. Miles Bennell (Kevin McCarthy) demands the other doctors believe his wild tale and take his dire warnings about oncoming danger seriously. At last, Dr. Hill (Whit Bissell) has compassion and agrees to listen to his fantastic story. We then enter flashback mode.
Miles has been summoned home to Santa Mira, California (Mill City in the book) by his nurse Sally Withers (Jean Willes). En route to their clinic, Miles suddenly brakes to avoid hitting a little boy, Jimmy Grimaldi (Bobby Clark, now going on 77 years old). Despite what it looks like, Jimmy isn’t trying to avoid school or bullies. Instead, he’s terrified because his mother supposedly isn’t his mother.
The second such case Miles encounters is that of Wilma Lentz (Virginia Christine), who’s insistent her uncle Ira, who raised her, isn’t Uncle Ira anymore. She says everything else about him is exactly alike, right down to his memories, but the emotions aren’t there. He seems dead inside.
In the middle of dealing with these strange cases, Miles rekindles his relationship with his old high school sweetheart Becky Driscoll (Dana Wynter), Wilma’s cousin. Both of their first marriages ended in divorce, but they’re now both older and wiser, and eager to begin fresh.
Though Miles’s colleague Dr. Dan Kaufmann (Larry Gates), a psychiatrist, assures him these people are just suffering from a mass psychosis and can’t possibly be telling the truth, everything Miles thinks he knows about medicine, psychology, and reality is shattered when he visits his friends Jack and Teddy Belicec (King Donovan and Carolyn Jones) that evening.
Out of nowhere, a body appeared on the Belicecs’ pool table, wrapped in a sheet and with blank facial features, like a coin that hasn’t been struck yet before leaving the mint. He leaves no fingerprints either. Things go from bizarre to hair-raising creepy when they realize he has the same height, weight, and general features as Jack. Then a bleeding cut appears on his hand, exactly matching the cut Jack just got.
Miles takes Becky home, but is so disturbed by the feeling that she’s in grave danger, he presently returns. Becky’s father is emerging from the cellar, which strikes Miles as odd. When Miles goes into the cellar, he finds Becky’s incompletely formed double. In terror, he rushes upstairs and carries the sleeping Becky into his car.
Dr. Kaufmann is called to investigate the two doubles, but they’ve both vanished by the time he arrives on each scene. He believes the one at the Belicecs’ house was real, and that Miles was so jittery about it, he hallucinated seeing Becky’s double. Police Chief Grivett presently reports a body matching the description of Jack’s double was seen on a funeral pyre.
The next day, Miles finds Jimmy happily reconciled with his mother and asking to go home soon (after staying overnight with his grandma). Wilma likewise cancels her psychiatric appointment and reports she no longer thinks Uncle Ira is a phony.
In the evening, Miles discovers giant seed pods on his property, which presently open to reveal more bodies, surrounded by foam. These bodies look like Miles and his friends. In terror, he phones the FBI and is informed all the lines are dead. Every operator reports this, in every city he tries.
Miles takes a pitchfork to these pod people and sets them on fire, then tells the Belicecs to flee and get help. He and Becky will take another route and try to reach someone, anyone, who can stop this menace in its tracks.
After stopping by a gas station, Miles discovers two pods in his car. He immediately destroys them, but it’s like fighting a mighty enemy army with pebbles and shoestrings. One by one, everyone Miles knows is turning into a pod person, and more are constantly being brought in.
Miles and Becky go on the run, trying their best to evade capture and sleep. If they fall asleep for even one minute, they’ll be replaced by an emotionless pod person. But if they manage to make it to another town, there just might be hope to save humanity.