4 stars

When the junior soccer team and coach who went missing inside a vast underground cave system in Thailand in 2018 were discovered, it was said that finding them had been the easy part. Getting them back to the surface alive was so difficult that many thought saving them was improbable without loss of life.

The massive international rescue mission in Chiang Rai province that managed, against all the odds, to bring every single one of them back to safety after 18 days underground, is incredible, even now. The Tham Luang rescue is a spectacular achievement on many levels that deserves to be told and retold many times.

Perhaps it is also in part testament to the boys and coach themselves, to their sense of being a team, and to the meditation and calmness they practiced during the ordeal.

It was inevitable that Hollywood would obtain the rights to this story. Yes, a big budget feature is due out next year, but it is hard to imagine a more stunning version than this doco, The Rescue. It's directed by the American filmmaking couple, Elizabeth Chai Vasarhelyi and Jimmy Chin, who brought us Free Solo, which they shot as they made their way up El Capitan alongside the first man to climb the Yosemite monolith without ropes.

Watching that remarkable doco, we knew the free climber would make it, but it was still intensely compelling. Similarly, even though we know what happened the broad outline of what happened during the Thai cave rescue, this is a thrilling and compelling dramatic experience. It is another National Geographic production.

The intensity of The Rescue lies in the first-person interviews and in the footage, some never before seen, of the rescue underway inside the caves. Even the cavers, on whose rarefied expertise the mission impossible depended, could hardly dare hope they would manage to bring all 13 people out alive. But what was the alternative?

Everything seemed pitted against success. Oxygen in the chamber where the boys were sheltering had dropped below life-sustaining levels. Diving inside the cave system was like white water caving. The monsoon rains had arrived early that year. Some of the 11-16-year-olds couldn't swim, and any one of them, in their unconscious, sedated state, could drown in their own saliva.

There was a natural, understandable hesitancy among officials about taking bold and dangerous steps, until they became the only option. Excerpts from the news channels about progress are sometimes painful to watch, revealing an expectation that all the effort could only end in failure.

The world's top cavers, brought in from countries like Britain, China, the US and Australia, were ready, but they had never done anything like what they were being asked to do here. Some reacted to the desperate but ultimately successful plan to sedate the team and swim their inert bodies out one by one, with dismay. If it was a horrible idea, it was the only one going.

Rehearsal of the concept over several days helped convince Thai officials that there was method to the madness. The journey would involve a 1.8-kilometre swim over two hours, with each of the boys facing downwards, their hands tied behind their back, for their own safety. In the words of the Australian anaesthetist and caver Richard Harris, whose crucial contribution to the mission is well known, it felt like euthanasia.

Other divers recall their fear and acute anxiety of failure while having strong determination about getting their precious cargo out. It is hard to imagine a script any more scintillating than many of the real-life recollections here.

In-depth interviews with the two British cavers, Richard Stanton and John Volanthen, who first found the boys, reveal singular, private men who took to caving after they felt they hadn't succeeded at regular sports. The stunning success of the cave rescue was, if you like, justification for their minority sport, a weekend hobby.

The miraculous rescue was a massive effort involving 10,000 people from different cultures, with different languages and different ways of life, all working to the same end. It is an amazing testament to these many people, and how good is that?