Septien

Forget the title, it won't help you as you step into the world of Cornelius Rawlings - a sort of lost prodigal son who we meet as he returns to his family's farm in the Tennessee backwaters after an absence of 18 years. "Jesus Christ," says his brother Amos when he spots him - and it's true, his bad-ass beard does have a look of Christ from the wilderness; one of the many biblical echoes that crop up in this story that is ultimately guided by love and redemption. Back home, things are pretty much as they ever were, with Amos spending his days in the barn creating surreal pastel artwork blending satanism and sports, while elder brother Ezra, all frills and goodness, plays "mummy bear", cleaning and cooking and church-going. Out in the backyard, is Wilbur Cunningham, a member of the extended family, who lives in a large tyre and is far from the sharpest tool in the box.

By now, you're sensing that Kansas is little more than a dot on the horizon, and yet despite the down-the-rabbit-hole feel of the plot - which could have been plucked from any number of horror films - there's still something touchingly human and normal about these characters. If all that isn't odd enough, an explosion of faeces in their bathroom leads to an overflow of excrement of an altogether more pyschological kind when a plumber with a face from their past sets in motion a chain of events that will make them all confront their emotional demons.

Michael Tully says in his directorial notes for Septien that he had "never seen all these tonal elements combined in a feature film before". It's true that this exact blend of southern gothic, quasi-horror and surreal character comedy may not have be previously concocted. But Septien employs the sort of banal characters pushed to the verge of, yet not into, caricature that was the lifeblood of The League Of Gentleman's Royston Vasey. It is also fair to say it is a kissing cousin of last year's Brit low-budget indie Down Terrace, which mixed extreme ordinariness with extreme violence to create an air of disturbing black humour and with Sundance 2010 alumni Lovers Of Hate, which took what could have easily been a horror film set-up and played it for emotional drama and laughs.

Robert Longstreet - who after years of bubbling under is in four films this year at Sundance - surely must be on the verge of becoming a well-known name. If there's any justice he will, as his performance here is exceptionally well nuanced, taking Ezra into the realms of camp without ever making him seem ridiculous. He is matched step for step by Onur Tukel - who also supplied the superb surreal artwork that his character is seen creating out in the barn - and Tully himself as Cornelius, a simmering presence at the film's heart.

The combination of its backwoods horror-style set-up, an excellent score from Michael Montes - at once childlike with a fairytale edge, yet quietly menancing - and the off-kilter but nice-as-mom's-apple-pie characters gives the comedy, of which there is a considerable amount, its disturbing edge. The only problem occurs with the plot, when after carefully constructing his family of believable characters, Tully drops in another one with barely an introduction but upon whom much of the last third of the narrative depends. But if there is, ultimately, perhaps one too many pieces for his plot jigsaw, that is surely better than too few. An oddball curiosity with a lot of heart that like cinema to take them a little of the beaten track.

Septien is available on VoD in the US. See sundanceselects.com for details