“Look! You fools! You’re in danger! Can’t you see? They’re after you! They’re after all of us! Our wives, our children, everyone! They’re here already! You’re next! You’re next! You’re next!”

Those are the harrowing words of Dr. Miles J. Bennell (Kevin McCarthy), the local doctor of a small California town called Santa Mira. At the beginning of the film, he insists repeatedly to a psychiatrist that he is not insane. Yet the story he tells isn’t winning him any believers.

It all starts the day when Dr. Bennell returns from a medical conference. His secretary, Sally (Jean Willes), picks him up from the train station and informs him that an unusual number of patients had called, wanting to talk to Miles specifically. Once back at the office, Bennell returns their phone calls only to be told that they had changed their minds about whatever had been bothering them.

Although perplexed, Miles chalks it up as just one of those odd occurrences. It isn’t long, however, before he realizes that the crises hasn’t passed.

A select few patients inform the doctor that their loved ones aren’t themselves anymore. Mind you, they mean this literally. Peoples’ husbands, wives, and children have supposedly changed into emotionless carbon-copies of their former selves.

One of these people happens to be the cousin of Becky Driscoll (Dana Wynter), an old flame of his. The good doctor naturally agrees to pay Becky’s cousin a visit and tries to talk some sense into her. Try as he might, Miles can’t change the woman’s conviction that her father is not her father. So he refers her to his psychiatrist colleague, Dr. Kauffman. Miles finds out from Kauffman that Becky’s cousin hasn’t been his only case these past few days. Dozens of patients have come in exhibiting this “mass hysteria.”

Soon enough, Bennell finds out that mass hysteria cannot always be explained away by medical terminology or conventional reason. There is indeed something unnatural taking place in the homes and offices of Santa Mira and countless other towns like it. Something that is growing and systematically creeping across America. Before the film ends, the respectable doctor will find himself in the shoes of his hysterical patients.

One of the more remarkable things about Invasion of the Body Snatchers is that it has every reason not to work. It had a fairly standard 1950’s science fiction plot, a shoe-string budget, and no A-list actors to speak of. It was the perfect recipe for another Plan 9 from Outerspace.

Yet even after fifty years and two inferior remakes, the film still has resonance. It has all the sensibilities of a big-budget movie without any of the hokey technological limitations of a small one. Rather than focus on the how or why, Invasion keeps its sight on what’s important: the effect the menace has on people. Both leads are attractive, charismatic actors that deliver their lines like velvet. The paranoia crackles through the town like a shot nerve. The danger, although not overt, is always present. The cinematography is crisp and atmospheric.

More than that, it’s a feeling that Americans can still relate to. Film historians have often called Invasion of the Body Snatchers an allegory for the Red Scare of the 1950s. Although both the filmmakers and Kevin McCarthy deny that McCarthyism was ever a conscious plot point, one must wonder how much of a subconscious influence the constant barrage of warnings about Communists and the fifth column had on the creators of the film.

“They’re after you. They’re after all of us!” was the rallying cry of McCarthy’s modern-day witch hunt. “They” are in every town and city, watching and waiting, an ever-present threat. We might not be able to see them, but we can sense them. They could be anyone and, if politically necessary, will be anyone.

Don Siegel, who directed the film, stated that he was forced to add the first and last scene to create a frame story in order to satisfy censors who thought that Bennell screaming on the highway would be too disturbing to moviegoers.

One must wonder: what could possibly disturb people about the words “You’re next! You’re next!” being shouted at them through the theater screen?