The world is what it is. The latest knotty drama from Asghar Farhadi entered history when Donald Trump’s travel ban helped it towards an Oscar for best foreign language feature. It deserves to be known for more than that.

True, The Iranian film is not quite up to the standard of earlier Farhadi pictures such as A Separation or About Elly. It is drier than either of these predecessors. It feels just a bit hemmed in by its literary high concept. But this remains the work of a singular storyteller who conducts actors and coaxes narrative arcs as well as any living director.

The picture begins with a moment of high metaphor. Rana (Taraneh Alidoosti) and Emad (Shahab Hosseini), amateur actors working on a production of Arthur Miller's Death of a Salesman, are inconvenienced when, as a result of nearby construction, a huge crack appears in their Tehran apartment. Oops, looks as if they are not set to live happily ever after.

Some time later, in the flat to which they have been relocated, Rana suffers a puzzling assault. We never learn exactly what happened, but an individual did enter the bathroom when she was showering. Is Rana pretending when she says she can remember little of what happened?

The outer narrative of The Salesman is very obliquely related to the Miller play. Both stories are driven by a sense of shame and impotence. But Emad is a more forceful presence than Willy Loman. He makes it his business to track down the culprit. Along the way, he discovers that a sex worker previously occupied their current flat.

Like A Separation, the new film is concerned with the ways that doubt and dishonesty undermine relationships. Alidoosti and Hosseini tease out the threads with great subtlety and intelligence. But the film does lose focus as the detective story meanders down too many distracting paths. At least one significant character is introduced too late for us to get a proper grip on his motivations.

Still, it is always worth puzzling out what Farhadi is up to. A serious film for serious times.