This debut feature from Welsh director Joshua Trigg exudes an unassuming virtuousness from every pore, thanks in no small part to a dignified performance from child actor Itthiphone Sonepho. In the kind of serendipitous road-trip story more often seen in an American context, he plays Laotian orphan Satu, whisked off from the Buddhist temple that raised him on a quest to find his mother by urban runaway Bo (Vanthiva Saysana).

Bo, in contrast, is fleeing her family: after her mum’s death, her father has taken to violently abusing her. An aspiring photojournalist, she is looking for a story in order to enter a competition; Satu’s situation, abandoned by his parent (Sonedala Sihavong, seen in flashback) with a letter hinting at her whereabouts in Vietnam, is just the ticket. So when the discovery of unexploded bombs on the temple grounds means it may be evacuated, the pair hit the road on her dirt-bike, with Satu’s pet rabbit Jeobong in a cardboard box.

Trigg has the eye of a photojournalist himself, honouring the lush Laotian landscape in warm, attentive and picturesque cinematography. He keeps his protagonists’ passage through it fairly uncluttered events-wise: their bike breaks down; Satu is offended by Bo having lied about being a fugitive; they encounter some would-be human traffickers. But this simplicity is both a strength and a weakness; paradoxically, maintaining it is no simple matter. Trigg injects pace as the authorities close in on Bo, and some awkwardly staged pursuits break up the surrogate-family intimacy he has delicately fostered between her and Satu.

Using Bo’s voiceover to make explicit salient themes also smacks of over-adornment when Trigg is clearly able to convey them visually and dramatically. The importance of storytelling in forging a sense of self is clearly Trigg’s priority – and more than adequately encapsulated as Satu’s tale comes to rest, in a very Buddhist fashion, under a tree. Playing the role, Sonepho has a kind of stubborn wisdom beyond his years that – in tandem with equally resolute Saysana as his chaperone – sustains this moving parable about self-responsibility.

• Satu – Year of the Rabbit is at the Prince Charles, London on 14 March, then tours.