Never mind The Fault in Our Stars. If you really want screen teens to break your heart this summer, don't miss Diego Quemada-Díez's superb new drama, The Golden Dream. The film, a nail-biting and unsentimental tale of three youngsters as they journey from the slums of Guatemala city towards Los Angeles, has already garnered dozens of major prizes on the festival circuit, including silverware from Cannes and Dublin.

It is, reputedly, the most heavily decorated film to emerge from any region of the Americas. That, one feels, is only right and proper: the film’s themes sing with urgency, and its emotional impact is unrivalled among this year’s releases.

“I wanted to make something like an epic poem,” says the film-maker, who spent many years collecting testimonies from migrants. “I wanted to give a voice to those risking their lives to help their loved ones to solve the problems of inequality. They are heroes but they are also human beings living in a world of double standards. The circumstances that create people’s desire to migrate are more and more prevalent, just as borders are increasingly militarised. Post-Berlin we thought we were tearing down walls. But the walls between us – races, nationalities, languages – are still there and more reinforced than ever.”

For Quemada-Díez, the theme of interconnectedness at the heart of The Golden Dream isn't merely some ill-defined, new-age blather. It's a genuine social and aesthetic manifesto: "The clothes you and I are wearing, the furniture you're sitting on: somebody made those things. Somebody else transported them. Somebody else collected the food we eat. This isn't an illusion. What happens to one of us happens to all of us. Part of the journey in the film is the move away from our western concept of individuality toward a recognition of our interconnectedness as human beings."

Collecting stories

Sure enough, there's something of the folk ballad about The Golden Dream. All told, the Spanish-born Quemada-Díez spent more than six years collecting stories from some 600 migrants to weave into the fabric of the screenplay.

“The details that you use to construct the story are very important,” he says. “The girl who cuts her hair and covers her breasts and dresses like a boy – that’s a detail that comes from testimony. All the details are from life. But you have to have something to say about them. You have to have hope, a utopian concept. I don’t buy the idea that an artist should be neutral. If you need to express yourself, then you must have something to say. I am not interested in naturalism for naturalism’s sake. I love that idea of Robert Louis Stevenson that a work of art must be equal parts realism and idealism.”

In this same spirit, the film-maker saw more than 8,000 kids before he settled on the three non-professional lead actors. The youngsters – Karen Martínez, Brandon López and Rodolfo Domínguez – would ultimately win a special ensemble award at the Cannes Film Festival.

“Casting is key, because even though you have a dramatic structure and a rough outline of dialogue, you need some improvisation,” says Quemada-Díez. “You need the actors to say the lines as they would say them, in their words. You worry about creating the context, but not the behaviour. You never tell them how to behave. The best direction is indirect. It has to be almost invisible.”

As the film opens, Sara (Karen Martínez) cuts her hair and disguises herself as a boy before she and her friend Juan (Brandon López) depart for a better life in the north. Along the way they face an untold number of would-be kidnappers, murderers, corrupt officials and Chauk (Rodolfo Domínguez), a young Indian, who, at first, inspires nothing but racist disdain in Juan.

“Juan is this selfish, individual kid,” says Quemada-Díez. “He has a very westernised view of himself and the world. Chauk believes in a different cosmogony and has a different set of values. He is capable of sharing with people. He takes care of the land. I wanted to create the story through that conflict and character development.”

The plaudits have been a long time coming for writer-director Quemada-Díez. He has spent more than 20 years working his way up through the ranks. Since 2006 he has worked as a member of the camera crew for talents as diverse as Joel Schumacher (on The Number 23), Alejandro González Iñárritu (on 21 Grams), Tony Scott (on Man on Fire), Fernando Meirelles (on The Constant Gardener) and Oliver Stone (on Any Given Sunday).

Ken Loach influence

These directors have made rather less of an aesthetic impact on Quemada-Díez than Ken Loach. The Spanish director worked with Loach on three films – Land and Freedom, Carla's Song, and Bread and Roses – and is considered by many as a spiritual heir. In keeping with the English director's methodology, Quemada-Díez shot in narrative sequence using a semi- improvisatory approach. He kept the camera at eye level and rejected swooping cranes in favour of a human perspective. The actors were unaware what fate had in store for their respective characters.

“It was almost like making a documentary,” says Quemada-Díez. “The original concept was that the kids didn’t know what was coming. They needed to live an experience, to live an adventure. It had to feel real to them. And around them there are real migrants and real trains and real people from the towns we passed through. We were trying to make a film that had as many truths as possible.”

Unsurprisingly, his former mentor is a fan. “Ken came to see it with his wife and his producer Rebecca [O’Brien]. I was very nervous, because he is very exact about film. His support has been great.”

The Golden Dream is at the Irish Film Institute