Domestic discord gives way to a transformative romance on a struggling Yorkshire farm in the assured debut of director Francis Lee. God's Own Country is a film that reaches beyond its modest setting and low-key love affair to make a potent plea for countrywide change. Fluid photography and achingly honest performances merge magnificently, with the story of love amidst the livestock considerably more charming than it sounds.

Josh O'Connor captivates as Johnny Saxby, a young Yorkshireman living an unhappy existence with his sour grandmother (Gemma Jones) and disgruntled father (Ian Hart). He's burdened with the upkeep of the family farm by day, following his father's stroke – a responsibility for which he receives no thanks – and drinks himself stupid by night; a hook-up in the back of a van bears comparison with his aggressive inspection of a pregnant cow, minus the affection afterwards.

Things get interesting for Johnny when Romanian migrant Gheorghe (an instantly appealing Alec Secareanu) arrives for a week of seasonal work, assisting with the lambing. Swarthy of appearance and kind of heart, his sensitivity to barbs and enthusiasm for biscuits also marks him out. Theirs is a liaison that begins as primordial passion, consummated against the land itself, but that grows more intimate as the bitterly closed Johnny opens himself up to the possibility of a better life.

Writer-director Lee grew up on a Yorkshire farm and is fittingly respectful of the graft, whilst acknowledging the rewards of such work and the majesty of the landscape. There's real satisfaction in the gradual softening of a hard lad and joy in the passion and laughter that acts as a salve to the scowling oppression of the Saxby home, and the film shows the hidden humanity of those who at first seem almost comically unwelcoming.

Although Jones and Hart are underused, Lee beautifully illustrates how personal disappointment begets cruelty to others – a cycle that cannot easily be broken from within. With Gheorghe as capable as he is kind, this outsider's value to an insular, damaged family unit goes beyond his potential as a partner for Johnny. In a divided country crippled by fear of foreigners, the wider point is clear.

Screening on Wed 21 and Thu 22 Jun as part of the Edinburgh International Film Festival 2017. General release from Fri 1 Sep.