Directed by David Mackenzie. Starring Luke Treadaway, Natalia Tena 15A cert, gen release, 80 min

THIS IS THE sort of funky-legged film you want to like. It’s got a neat central premise. It makes good use of its cannily chosen setting. Unlike too many mainstream blubby dramas, it demonstrates a sincere belief in the power of romantic love. What a shame so much of it seems so cack-handed.

The erratic David Mackenzie, director of Young Adamand Asylum, has brought his hand-held camera to the T in the Park music festival near Edinburgh. Luke Treadaway, so good in Brothers in the Head, plays one half of an American synth-pop band named The Make. Within moments of arriving, he encounters Morello (Natalia Tena), stroppy singer with a sub-riot grrrl band. From the second they begin bickering, you know in your soppy soul that, after becoming metaphorically manacled together, they will eventually fall into each other's arms.

Hang on. Forget about metaphors. A deranged preacher rushes from his charabanc and – for reasons never satisfactorily explained – literally handcuffs the rockers to one another. Then he vanishes. It's The 39 Stepswith power chords.

It’s a nice idea, but unfortunately neither actor seems comfortable with the level of improvisation required. Uninteresting conversations trickle away into nothingness. The hipster self-regard, whether meant satirically or not, very rapidly becomes hard to bear. One can never quite escape the notion that this is a short film stretched painfully to feature length.

There are certainly things to admire in You Instead. Mackenzie busies about the festival and, offering us a great deal of rain and a little too much generic indie pop, presents a portrait of the event that takes in the best and the worst of riff-based outdoor entertainment.

But, rather than powering along like an early Ramones song, You Instead– with its long improvised sections and indulgent deviations – ends up coming across like one of the more tuneless cuts from a Grateful Dead bootleg. Such things did, as I recall, quite often run to 80 minutes.