Confined to a dingy motel and desperate for money, Nash secures work with a man who has plenty - Carver: in a symbolic touch, his first job is to clean out a house whose evicted occupant blocked the sewers. Gradually, a pact too awful to be called Faustian is formed, and Nash ends up visiting on others the indignity inflicted on him.
Bahrani, the son of Iranian immigrants, said his film has struck a nerve in audiences who did not connect with the subjects of earlier, immigrant-based stories.
"The economic pressures that affect the majority of people are not often depicted in films. But now middle-class America is really struggling to make ends meet. It's the majority of people now."
That majority, the 99 per cent of the Occupy Wall St rhetoric, is referenced in the title (which has a more specific narrative explanation). Bahrani says he was surprised the toxic-mortgage housing slump had not previously captured the imagination of filmmakers.
He chose Florida, the most evocative of the four epicentres of the crisis, since it was a synonymous with the dream of the carefree life in the sun (the setting, Orlando, home to Disney World, adds to the irony). He travelled south on research trips, talking to fraud attorneys and brokers and sitting in foreclosure courts as they worked through the so-called "rocket docket", determining the fates of families "in 60 seconds flat".
Bahrani said the pact-with-the-devil story became apparent to him on the first trip. "I knew that a lot of the people were struggling financially and wondered what if? I hadn't actually come across people who were doing it, but once I had started writing it, I did. I spoke to one real estate broker who had two people who had worked for him that he had evicted.
"Andrew went down on a research trip and ended up speaking to a guy in Home Depot-type place who told him his story and it was basically the story of the film."
The atmosphere in Orlando was highly charged: "Everybody was carrying guns and there was so much corruption and so many scams and as I got into writing the script and saw that there was all this violence, I thought, 'my God we are writing a thriller here'.
"It has the typical structure of a gangster movie where Rick is pulling Dennis into the fold and Dennis is having to pass tests as he gets deeper and deeper. It added a tension and a pulse to the film that became relentless and we shot it that way and edited it with a rapid pace and scored it in a cold remorseless way, too."
The Nash character gives a bitter twist to the idea of the American hero " a man who will protect his family by destroying others'. That, says Bahrani, is the moral ambiguity that drives the film and hooks us in as an audience.
"Rick's a Gordon Gekko greed-is-good kind of character but I find myself sympathetic to him too, when he talks about how he doesn't want to get demolished by the system and he doesn't want his kids to be in trouble.
"There's a scene when Dennis asks Rick, 'Is it worth it?' Rick answers, 'As opposed to what?' Michael said, 'that's the most important line in the scene, right?' and I said, 'that's the most important line in the film'. 'As opposed to what?': what else are we supposed to do?"
Lowdown
What: Andrew Garfield and Michael Shannon star in 99 Homes
When: In cinemas from Thursday
