ALTHOUGH the film is fformed as a ghost story, the opening of Km 31 claims that it is "based on real events". That proves as hard to swallow as the film itself, a Mexican production heavily influenced by, and sharing several visual motifs with, such recent Japanese horror movies as Dark Water, The Grudge and The Ring.

The film opens arrestingly as Agata (Iliana Fox) is driving along a deserted highway on the outskirts of Mexico City by night, and crying after an argument with her boyfriend Omar. When what seems to be a child flashes across her path in a blur, Agata stops her car, gets out and is run over by another driver. In a house nearby, her identical twin sister Catalina (also played by Fox) telepathically senses Agata's fate.

Km 31 takes its title from the signpost at the point in the highway where this incident occurs. The area is revisited as Catalina tries to comprehend what happened while she hears screams of help from her sister, who is in a coma.

Omar offers his assistance, as does Catalina's long-time Spanish friend Nuno. A gruff detective continues his obsessive quest to solve a series of mysterious deaths at the site. There are revelations of sibling rivalry between the twin sisters in childhood and its tragic consequences. And a strange elderly woman, who lives in woods off the highway, relates a local legend.

Writer and director Rigoberto Castañeda exhibits a flair for the genre and for conjuring ominous imagery and atmosphere, but the film is undermined by the sheer familiarity of recurring shots of fleeting furtive figures from its Japanese counterparts.

Most disappointingly, Km 31 is short on suspense and proves none too scary or unsettling, despite the frissons generated in the spooky establishing scenes.