Mid-life crisis wife Catherine hires a seductive hooker, Chloe, to 'test' the loyalty of hubbie David (a very dangerous course of action)... and the rest will be revealed as you watch this adaptation/remake of the 2003 French drama Nathalie.
This is good, though Atom Egoyan's style, best suited to enigmatic arthouse films, does seem a little out of kilter when this film takes a turn into stalker/thriller territory.