A deceptively short film (it runs a mere 80 minutes), Most Beautiful Island is an increasingly unnerving trip to an unexpected destination. New York footage follows different women, one per shot, navigating serial crowded spaces. Eventually a shot frames Luciana (Spanish writer-director Asensio, from Madrid). Titles. Then she’s speaking Spanish on the phone to her mother who wants her to come back. She won’t because of of her past (which is never explained).

She visits Dr. Horovitz (David Little), attempting to scam a consultation off him without paying. (This is the US, remember, where medical treatment isn’t free at the point of need to all as in the UK, but available for a $75 fee for those lacking a social security number. A chilling glimpse of the system after which the UK’s current neoliberal government might want to model the NHS.) She takes a bath, peeling tape off the wall to admit a cluster of cockroaches which she watches swim for their own survival as she relaxes.

Work. She and her friend Olga (Natasha Romanova) wearing vests, hot pants and beaked masks regale passers by with the slogan: “the best chicken in the Big Apple”. Luciana is sick of poorly paying gigs like this. As they chat in a cafe after, Olga gets a text for a gig tonight which she can’t do because she’s double-booked. So she offers it to Luciana. $2 000 for attending a party and you don’t have to do anything you don’t want. You need to wear high heels and a black dress. So Luciana has to buy a black dress. She finds a way despite lack of funds. There are other obstacles to negotiate – a missed text telling her she’s babysitting now and has to pick up the children (she’s late), hiding her backpack and possessions in a bin outside the building as she’s not allowed to take it to the party.

And the party itself. Watched over by a menacing doorman (producer Larry Fessenden) and told what to do by self-assured hostess Vanessa (Caprice Benedetti), Luciana and five other women stand in their designated, numbered chalk circles. They are inspected by wealthy guests, mostly males in suits, who will bet on the girls behind closed doors. Luciana was supposed to replace Olga, but Olga is not only present but also appears to have recruited several other girls. No-one will tell Luciana what the game involves. Eventually, she and Olga are chosen…

The first half hour lifts the lid on the immigrant experience in New York. Women like Luciana and Olga have their reasons for leaving their home countries and can’t go back, but now find themselves in precarious situations. They’re the global underclass and the game which they’re paid handsomely to attend is a divertissement for rich and powerful guests. The script is loosely based on an unpleasant if bizarre personal experience of Asensio’s and what subsequently transpires is horrifyingly believable. Alienating Big Apple imagery anchors the piece: shared apartments, busy streets, cab interiors. A pavement trap door leads down to a literal underworld of claustrophobic lift and (in US vernacular) ‘bathroom’ interiors, impersonal corridors and and brutal cement basements. In this cold environment the party game will play out.

Yet even as Luciana scams her way towards the mystery beyond the door in the hope of financial salvation, in passing there are hints of something better. The world isn’t just kids threatening that their mother will replace their babysitter because she’s late again: it’s also a place where a shopkeeper, seeing someone in trouble, will not only allow her a few days’ credit to get her out of a tight spot but also slip her a free sweet to help get her through the bad times.

Made quickly on a meagre budget, Most Beautiful Island is a more powerful film than numerous more polished, bigger budgeted films out there. We aren’t going to reveal its game except to say it’s most definitely one you want to experience. It is out in the UK on Friday, December 1st, and it’s available on BFI Player just after Christmas.