Rural Scotland has given culture a fair variety of creative weird. The folk horror of The Wicker Man. The psychedelic ramblings of The Incredible String Band. A few of Iain Banks’s off-centre novels. Now Louis Paxton makes a fascinating feature debut with a film that alternates briny whimsy with something more sinister. Not all of it works, but it’s an honest film that dances to its own irregular beat.

Domhnall Gleeson is on good form as one of his trademark amiable shy guys (see also Frank, About Time and The Paper). On this occasion he plays Daniel, a council employee who, happier skulking in a corner of the office, is dispatched to evict siblings Isla and Sandy (Gayle Rankin and Grant O’Rourke) from their occupation of a remote northern isle. “We have an uninhabited island that is actually inhabited,” his boss tells him. We are already aware the pair, stranded here since the death of their parents 30 years ago, have constructed a sort of theology around their peculiar lives. They wail at the sky. The threat of “incomers” hangs over them like a potential apocalypse.

It is impossible not to think of The Wicker Man as the nervous Daniel, easily observable in red and yellow anorak, strolls up the jetty and approaches the weird twosome, both dressed as ragged crows (or maybe dun puffins). Soon enough, Isla and Sandy have the visitor tied to a bed frame. Paxton’s script has great fun pointing up misunderstandings. “I do believe in all the animals; I just don’t believe in eating any of them,” Daniel wearily explains when they scratch heads at his vegetarianism.

The three core actors bump against each other with admirable comic invention. The siblings are oddballs alone and (to this point) unmolested in their own oddball empire. Daniel is an oddball in a society that would prefer him to conform. It is not giving much away to say they begin to reach understanding as raw music and elegant animation swells the eccentric atmosphere.

It is a shame Paxton can’t find a way out of the puzzles he has set for himself. Indeed, the too-neat ending feels like a betrayal of Isla and Sandy. Highly promising nonetheless. Watch out for John Hannah as a seal (no, really).

In cinemas from September 4th