It wasn't until after I'd watched this film that I read the theory about it being allegory for a religious cult. How that's the case I still have no idea. In fact despite a deceptively handsome (even in scenes depicting grisly murders) approach in everything from the production design to the film stock, I have no idea what any of it meant.

It's the story of a guy who seems to be a hermit living underground. Literally underground – he lives in a lair you reach through a trapdoor in the floor of a forest. After being chased out of his hole by two men and a priest, he arrives at the home of a well-to-do young family, asking if he can stay despite his unkempt beard and shabby clothes.

When his comments get too personal the husband beats the shit out of him, but for some reason that's never explained the wife feels some strange pull towards him and sets him up in the gardener's quarters without the husband knowing, sneaking food and clothes in to him.

After he's recovered a little he shows up at the door again, clean shaven and confident and asking to get work as a gardener. As soon as he does, more creepy members of his gang arrive, steadily ingratiating themselves into everyone's lives, from the wife who's still inexplicably in thrall to the previously scruffy antagonist to the cute young nanny and perfect kids.

The movie drip feeds a sense of menace. Physical and sexual threat hanging around Borgman and his henchmen the entire time and occasionally lead to some awful but clinically cold acts. Anyone from the outside world who gets too close to interfering with their plans for the family (whatever they are) are bumped off in increasingly inventive and gruesome ways.

Then there are a dozen subplots, narrative talismans and asides, none of which seem to make much sense on their own nor are related to the rest of whatever this twisted tale is about. A pair of angular racing dogs come into the designer house full of vitality, although it's never mentioned who owns them or what they mean.

After Borgman's gang fail to adequately dispatch an interloper and the cute little daughter of the family finds him crawling in the bushes beside the driveway, bleeding and asking for help, she picks up a large rock and drops it on his head to finish him off as if she's in on it.

There's a bizarre theatre performance in the newly renovated backyard and the bodies pile up, but what does it all mean? If you make the trouble to watch a film like this you aren't the kind of cinephile how needs everything spelled out, but you'll need more information than this. Visually arresting but essentially boring, establishing plot strands everywhere and never following them through.