Penny (Michele Hicks) first encounters Francis (Michael Polish) - a shy, softly spoken young man - in the Imperial Hotel on Idaho Avenue. She's a hooker, he conjoined with twin Blake (Mark Polish). Initially freaked, Penny runs, but returning for her handbag begins to feel sympathetic towards the pair. When Francis gets sick she calls a sympathetic doctor, but even as her affections - especially for Blake - grow, it becomes increasingly clear that the boys' life together is coming to an end.

Shot for $500,000 over just 17 days, Michael and Mark Polish's debut feature is revealed as a small triumph of talent over resource. Like Lynch's Eraserhead - a director with whom they share a deal of kinship - the siblings know to keep the canvass small and their ambition focused. Miracles are archived with a tin of paint and a talented cast. What they really take from Lynch, especially at the opening, is a sense of detail; their sets may be fairly sparse, but they know how to use them meticulously. Sputtering taps, flickering lights only look like clichés used obviously. M. David Mullen's camerawork is equally precise, and Stuart Matthewman's unobtrusive, Badalamenti-ish score is perfectly judged.

The film's ace, though, remains the brothers themselves - identical twins who spent the shoot wired into a constricting metal harness that allows them, with a little camera trickery, to convincingly inhabit the Falls' double skin. Their performances - imagine conjoined David Byrnes; gawky, unfailingly polite - are detailed, with separately developed personalities and, crucially, separate relationships with Penny. Only her part, despite some committed playing by the debuting Hicks, is underimagined: the obvious hooker with a heart of gold.

What this really is, despite all its real world trappings, is a fairy tale, more rooted but no less fanciful than Edward Scissorhands. If it borrows in particular from Lynch (there is a scene in which the brothers are cornered in a rundown park by gawping, camera-happy tourists that is straight out of The Elephant Man), and to some extent John Waters (Halloween is the only time they don't feel out of place), then the picture's broad sweep and evident compassion owes much to Burton.

As co-writers the brothers must also be held equally responsible for laying on the symbolism a little thickly in places (the wooden chopsticks is pushing it a bit), but for the most part - and especially in the tender, quiet close - Twin Falls Idaho remains a distinctive and highly promising calling card.