In a remote part of Germany, two American tourists, Lindsay and Jenny, find themselves trapped in a dark forest after having trouble with their car. Desperate for help, they eventually stumble upon the house of a strange retired surgeon, Dr. Heiter, known for his unconventional experiments. Although he initially appears to be a benevolent savior, they soon realize that his intentions are anything but altruistic.
After being sedated, the young women wake up tied in a basement, where Dr. Heiter reveals his disturbing plan: to create a "human centipede," a monstrous experiment in which he will surgically join three people so they will function as a single organism. The horrors of the doctor's mind unfold brutally, as he not only seeks to merge bodies but also to strip his victims of their humanity.
In a claustrophobic and terrifying journey, the girls, along with an unfortunate Japanese tourist who joins the nightmare, must find a way to escape from the clutches of this madman. The film is extreme horror that pushes the limits of what the audience can endure, challenging the notion of monstrosity within humanity. With unexpected twists and a chilling atmosphere, the story explores the dark corners of the human mind and the extreme vulnerability that can arise when the survival instinct is put to the test.