The subject of Eric Merola’s film at first seems small: how a private bank in the tiny mountain nation of Andorra found itself at the centre of a conspiracy. But its real interests are wide-reaching: the tactics used by the US government to disrupt Catalonia’s independence movement, and the modern face of American interventionism.

The hustle hinges on the murky section 311, a provision in the US Patriot Act that grants the Treasury Department sweeping powers in relation to any bank in the world, under the guise of protecting the world’s financial system. In 2015, the provision was used against Banca Privada d’Andorra (BPA) on the grounds that it was being used to launder hundreds of millions of dollars on behalf of criminal gangs in Russia, China and Venezuela.

The film outlines how the provision is used as a political weapon to protect US interests and undermine nascent threats – such as Catalan independence. It is a forensic examination of the circumstances surrounding the bank’s closure that attempts to illustrate the scale of America’s global influence and establish the innocence of the Catalan politicians at the centre of the scandal.

While fundamentally an exposé, The Andorra Hustle proceeds with the pace of a classic heist movie, powered by a pulsating soundtrack. Prominent figures from the Catalan independence movement get their say, including former presidents Artur Mas and Carles Puigdemont. An engaging look into an enormous corruption scandal that went almost entirely under the radar.

• The Andorra Hustle is on Amazon Prime Video from 4 September.