It sounds as hideously misguided as it does completely ridiculous: charter a fishing boat off the coast of India, head to a remote island populated by hostile Indigenous peoples famous for killing outside intruders, and then plan to ask them if they’ve heard of Jesus Christ.

The idea of folks shoving their religious and cultural beliefs down the throats of others never ends well, whether you’re talking Christopher Columbus landing in North America, or the Dutch East India Company setting up in South Africa. In the National Geographic documentary The Mission, the results are as fascinatingly horrible as they are predictable—even if you’re unfamiliar with the story that shocked the secular world a half-decade ago.

Determined to share his faith with the Sentinelese people of North Sentinel Island in the Bay of Bengal, 26-year-old Christian missionary John Chau embarked on a journey in 2018 to make contact, bringing gifts that included waterproof Bibles. The first two times, he was driven away by islanders who’ve repeatedly made it clear over the years they want zero contact with the outside world. (Proving the Bible has uses besides serving as a flashpoint for religious wars and inspiring right-wing intolerants, one of the arrows fired at Chau ends up stuck in the “Good Book.” Which, of course, he takes as a sign.)

On his third visit over a period of two days, the missionary—who, at one point, lived in Vancouver—is killed by arrows shot by the Sentinelese. The fishermen who, clandestinely, dropped him near the island then watch as his body is buried on the beach. Tellingly, his murderers are left alone by the Indian government, who monitor the island to make sure it remains isolated from the outside world.

Smartly, The Mission has Emmy winners Amanda McBaine and Jesse Moss focussing not so much on the Chau’s final fateful trip as much as what drove him to his death. The story is told through a mixture of interviews with friends and family, animation sequences, readings from his diaries, and old GoPro footage chronicling the missionary’s life-long love of the outdoors. 

That fascination with exploring the world as its most pure and unspoiled is matched only by Chau’s zeal for his faith, which becomes more and more entrenched as he transitions from a wide-eyed teen to religion-obsessed adult.

As is often the case, what Chau sees as a morally pure mission to do the “lord’s work” looks nothing less than wrong on every level to those on the outside. That’s especially clear when McBaine and Moss start spending time with evangelical American Christians, who half the time come across as bizarrely deluded—especially when running drills designed to teach self-defense to those who’ll be contacting hostile non-believers.

Fittingly—given we really have zero idea why we’re floating on this rock in space—what we’re ultimately left with in The Mission is endless questions. Why colonialism is still a thing aside, there’s a big one: what gives anyone the right to think their fellow human beings are interested in spending time with whatever God they happen to worship?

Chau’s father, a psychiatrist, is at a complete loss, wondering how someone so bright wandered so far into a world with no anchor to reality. Chau’s friends are split between those who—incredibly—remain devoted to the cause, and those who’ve accepted that, maybe, Jesus isn’t always the answer.

Older missionaries who’ve attempted to spread the word in other parts of the world, including the Amazon rainforest, reveal that they eventually came to realize that they’ve wasted their time. And that the communities they attempted to convert literally were left laughing when they departed.

As for how far adrift Chau ended up, consider his final diary entry: “Lord, is this island Satan’s last stronghold, where none have heard or even had the chance to hear your name?”

Think about what, quite justifiably, the Sentinelese do after he lands on the beach a third time: there’s nothing there to save him—not even Jesus, God, or his waterproof Bible. Read into that what you will.