Over a night spent apart, married couple Joanna (Keira Knightley) and Michael (Sam Worthington) are tempted into infidelity. But while he is enticed by a sexy new work colleague (Eva Mendes), she is drawn to a much-missed old flame (French star Guillaume Canet). For her directing debut, The Jacket writer Massy Tadjedin reteams with Knightley to create a credible and refreshingly non-judgmental morality play.
"This isn't a good connection," says English writer Joanna. "No it isn't," agrees her Australian husband Michael.
Of course, they're talking about the phone line. But they might equally be discussing their marriage following a jealous tiff the night before.
It all started when Michael introduced Joanna to his new workmate Laura (Mendes) at a party... having neglected to mention that Laura is a total fox.
After falling out and making up back at their swanky apartment, the very next day Joanna is left to stew in her imaginative juices in New York while Michael goes to Philadelphia on a business trip with Laura.
But while trying not to think of what sort of business her husband is up to, Joanna bumps into her old French boyfriend Alex (Canet).
Actually, the Gallic smoothie has planned the whole encounter. In town for just one night and anxious to show his feelings for her after all these years, he insists she join him for dinner with his similarly forward client (Griffin Dunne).
As the evening unfolds, Joanna and Michael both find trust and fidelity put to the test. Could well be another Anglo-Aussie match reduced to ashes...
The moral questions raised in Last Night are met with mostly honest answers. For many, monogamy is a tough game to master.
Unfortunately, writer-director Tadjedin never puts the audience in an awkward position as neither Joanna nor Michael elicit much sympathy.
This is partly due to the casting. Knightley can do vulnerable but she has never been the easiest fish to warm to. Even when she smiles, it's like facing a piranha with mascara.
Ironically, Mendes and Canet make a bigger dramatic impression from more intentionally thankless roles.
Relentlessly slappable though he is, Canet's Alex does appear haunted by genuine regret, while Laura is worthy of most respect by virtue of simply laying her cards on the table and seeing if Michael wants to play.
Whether you care about her characters or not (and you won't), Tadjedin does at least keep you guessing as to who will take the moral high ground come the end.
Even then, she doesn't make it easy.