Gus Van Sant’s thought-provoking Promised Land is set in small-town America, as Steve Butler (Matt Damon) and Sue Thomason (Frances McDormand) try to buy up the farms in rural Pennsylvania. They are working for a natural gas exploration company called Global Crosspower Solutions and there are apparently millions of dollars worth of the stuff in the shale under the green pastures around the town of McKinley.

Aside from trying to be a successful salesman, Steve is distracted too by the charms of a local schoollteacher, Alice (Rosemary DeWitt) who certainly seems interested in going out with him. But the path to true love is, yes, complicated.

At first it looks tempting, all this money which Global are promising cash-strapped local farmers, even if it means handing over land that has been in families for generations.

Indeed, the project looks like it might succeed, until an elderly man called Frank Yates (Hal Holbrook) speaks at a public meeting. Delivering his simple few words with the authority of age and experience - he has a Science Ph.D and is retired from Boeing - the old man points out the possible dangers that result from fracking, the means by which the natural gas will be extracted.

Fracking is a shorter term for the process known as hydraulic fracturing, which creates fractures in rocks by injecting fluid into cracks to open them further. The larger fissures allow more oil and gas to flow into the wellbore, from where it can be extracted. Fears about water table pollution are frequently voiced by objectors in connection with the process and the movie is certainly topical in the United States, as, indeed, it is in this country.

In Promised Land, so long as Global are in town, pride in the land holdings must play against the lure of easy money and the promise of a life seemingly free of debt.

But Steve and Sue must fight doubly hard when a young environmentalist called Dustin Noble (John Krasinski) arrives in town, telling a hard-luck story about how fracking ruined his family farm in Nebraska.

Ultimately, Steve and Sue are mere bit players in Global’s plans to buy as much land as they can throughout America. The unlikely pair muddle through, not without some pretty humbling experiences. The fact that Steve comes from an Iowa farming background himself means that the battle of wills in which he is a central player becomes conflicted as the saga evolves.

Van Sant, Damon and Krasinski (the two actors wrote the screenplay based on a story by Dave Eggers) have created a deeply compelling film about small town America in a period of economic depression.

Paddy Kehoe