“You can never have sex,” he explained. “Big no-no. Sex equals death.”
Writer-director David Robert Mitchell expands on this notion of fatal carnality in his impressive second feature: a skin-crawling jaunt into alcohol-fuelled teen angst that eschews the usual array of knife-wielding maniacs and masked bogeymen.
Instead, It Follows pits a group of unsuspecting teenage protagonists against the insidious threat of a sexually transmitted spectre that silently and mercilessly stalks each deflowered victim.
If the shape-shifting phantom catches and kills the terrified target, then the mark of death reverts to the previous carrier, and so on, back down the sexual daisy chain.
The only way to escape the malevolent force, which walks slowly towards victims and is invisible to the uninfected, is to pass it on.
Sex still equals death in Mitchell’s grim suburban nightmare but for the promiscuous, it’s also a temporary stay of execution.
An air of doom pervades the opening frames in which a nameless teenager flees her home and screeches away into the night in her family’s car.
“Just know that I love you both,” whimpers the girl into a mobile phone, lit by her car’s headlights.
The next morning, the girl is dead - her bones snapped and limbs contorted into a horrific tableaux.
The focus shifts to virginal 19-year-old Jay (Maika Monroe), who has decided to give herself to her boyfriend Hugh (Jake Weary).
A first night of passion culminates in Hugh restraining Jay.
“You’re not going to believe me but I need to you to remember what I say,” he barks, informing Jay that she is now the target for a manifestation that can take the form of family, friends or total strangers.
On cue, a naked woman staggers out of the dark.
Back home, Jay’s sister Kelly (Lili Sepe) and friends Yara (Olivia Luccardi) and Paul (Keir Gilchrist) console her but are reluctant to believe Hugh’s outlandish story.
When the youngsters clash with the sexually transmitted menace, they acknowledge the deadly threat and go on the run with Jay and neighbour Greg (Daniel Zovatto) to concoct a plan of action.
It Follows turns the screw on the horror genre, sustaining tension as characters wrestle with a mind-blowing dilemma.
Monroe is a sympathetic heroine, faced with a seemingly impossible moral conundrum: look over her shoulder for the rest of her life or pass on her fate.
Mitchell’s lean script ponders this agonizing choice with a level head, compelling us to urgently scan the horizon of each scene for the incoming threat.
One sequence, shot in a busy school corridor using a slowly rotating static camera, is deliciously nail-biting.
You can run but you cannot hide.