Keira Knightley, Sam Worthington, Eva Mendes and Guillaume Canet star in writer Massy Tadjedin's directorial debut, a romantic drama that explores monogamy in the 21st century.
Joanna Reed is struggling with writing her second novel in the rather grand New York apartment she shares with her estate agent husband Michael. At one of Michael's work functions, Joanna realises he is spending an awful lot of time with his hitherto unmentioned colleague Laura - and it's obvious that the two are mutually attracted.
So, when he announces that he's off on a business trip, and that the contingent includes Laura, Joanna naturally fears the worst. But, while he's away she bumps into Alex, an old flame who, it's intimated, was responsible for briefly causing Joanna and Michael to split up before they married.
The film flips back and forth, keeping track of the increasing temptation each character faces, as well their various discussions on the theme of fidelity. Will either succumb?