In the heyday of slasher films, the fastest way for characters to get themselves killed was by having sex. For a few bloodthirsty years following the release of John Carpenter's "Halloween" in 1978, audiences delighted in watching homicidal maniacs dispatch casts of copulating teens, before finally being vanquished by the one girl — and it was always a girl — whose virginal purity remained intact.

This dubious genre trope is given an ingenious spin in "It Follows," the sophomore feature by writer-director David Robert Mitchell. It turns adolescent sexuality into a sort of Ponzi scheme, where fornicating can mark you for death — unless you pass the curse on to someone else.

Young, blonde and beautiful, Jay (Maika Monroe) is ready to go past second base with her new boyfriend Hugh (Jake Weary), even though he has been acting a little weirdly recently. When he cuts short a date at the movies after apparently seeing a ghost in the theater, they finally get it on in the backseat of his car. But as Jay is enjoying some post-coital bliss, Hugh promptly drugs her unconscious, takes her to an abandoned building and straps her to a wheelchair in nothing but her undies.