The documentary Beyond Utopia follows various families as they attempt to flee North Korea. It is eye-opening and outstanding. In essence, it is a life-or-death thriller told in real time where the stakes could not be higher. I watched at home, via a screening link, with a twenty-something who did not look at her phone once. Could there be a higher recommendation?

The film has been assembled by the American director Madeleine Gavin who employed  a camera crew when it was safe to do so but otherwise made use of secret smuggled footage. Her way in is via Kim Seungeun, a South Korean minister who has bravely devoted himself – for reasons that become apparent – to helping North Koreans escape.

We follow two cases. The first is Soyeon, a defector living in Seoul who was separated from her son a decade before. He is now 17 and she is desperate to get him out. The other is the Roh family, who have made a run for it after learning that, because other family members have already defected, they are on the ‘banishment list’ and will be killed.

There are five in the family, including two little girls and a grandma who is 80. They’ve made it across the Yalu River into China – we see them sitting in a ginseng field, stricken with terror – and now have to somehow journey on through China, Vietnam and Laos, all countries that will return escapees to North Korea and almost certain death. Grandma is brainwashed, bewildered, and can’t believe that Gavin won’t kill her. In North Korea, we learn, there is no word for ‘American’, only one for ‘American-Bastard’.

Pastor Kim, who, no question, may be the greatest man who ever lived, has established an ‘underground railroad’ involving ‘brokers’ each step of the way. At first you assume the brokers are also good people but it soon becomes clear that they’re human traffickers who may not be trustworthy. You just have to hope.

At one point the Roh family have to be guided on foot through the Vietnamese rainforest at night but are led in circles until Pastor Kim agrees to give the ‘brokers’ yet more money. (It’s all funded by his church.) It’s phenomenally nail-biting. Your stress levels will go through the roof.

But there are some restful moments. At one point the family arrive at a safe house where they marvel over the shower that’s ‘like thunder’ and a television that they initially assume is a blackboard. The little girls discover a box of Ferrero Rocher, nibble cautiously, are not impressed, and who can blame them? All the while, Soyeon waits desperately for news of her boy.

Gavin juggles these two narratives while also expertly weaving in the history of North Korea and the first-hand accounts of those who have already defected. The revelations expose a regime that is horrifying – gulags, torture, public executions – and also batshit crazy. Did you know, for example, that pictures of Kim Jong Un must be hung prominently in every home and are subject to ‘dust inspections’? (Police turn up randomly in white gloves and just a speck of dust will merit ‘severe punishment’.)

The country also doesn’t have chemical fertilisers so citizens must use drop toilets and buckets and donate their own faeces to farmers. When a household cannot produce enough (there is a daily quota), they may steal the ‘poo’ from other families. It’s fascinating watching grandma process that her homeland may not be a ‘utopia’ and that she’s been lied to all her life.

It’s only in cinemas until the middle of next week so you may have to get your skates on. But if a twenty-something isn’t checking Instagram every two minutes to see who is using what face pack when, I don’t have to tell you it’s good.