Part documentary, part semi-improvised drama, Who Is Dayani Cristal? attempts to humanise the reams of statistics about migrants in North America through two entwined bits of storytelling. In one, director Marc Silver and his crew track state officials' efforts to identify a dead man found in the Arizona desert who had the words "Dayani Cristal" tattooed on his body, his only form of ID. Meanwhile, in the quasi-fictional strand, actor Gael García Bernal plays a migrant whose path follows the deceased's journey from Honduras to "el Norte". Along the way, he meets real people who recount their own motivations, fears and hopes. Only the most callous anti-immigration zealot could fail to find these stories poignant, but there's something awkwardly artificial about the dramatised strand, in which ordinary folks strain to pretend they don't know Bernal is a film star with a camera crew in tow. That said, he is, as ever, an immensely likable presence, using his fame and charisma to raise awareness about one of the big issues of the day. Bonus points for great camerawork.