Ippolita is a paralyzed young woman with serious mental problems stemming from the death of her mother. Her crisis of faith and the intervention of a well-meaning psychologist lead Ippolita to remember her past life as a witch during the Inquisition. Eventually, Ippolita becomes possessed and starts seducing local men, only to kill them. An exorcism seems to be the only solution to stop the madness.
From contemporary reviews, Geoff Brown (Monthly Film Bulletin) stated that "admirers of carbon-copy cinema-if any exist-will be well pleased with Alberto De Martino's The Antichrist" noting that it managed to emulate The Exorcist more closely than the Italian film The Devil Within Her.
In retrospective reviews, AllMovie gave the film a negative review, noting that "long stretches of not a lot happening are supposed to create suspense, but all they do is delay the inevitable finale, which was the original audience's entire reason for being there since they knew it was going to include elements of The Exorcist." The review concluded that The Antichrist "probably was intense, but that intensity has diminished over the years" and that the film was "for Italian horror collectors only."