You need to watch the best steampunk sci-fi movie on HBO Max ASAP

To watch the films of Hayao Miyazaki is to be transported to some of the most magical and imaginative worlds that have ever been realized on-screen. The Japanese filmmaker is generally regarded as one of — if not the — most talented filmmakers, and it’s not hard to see why.

Throughout his 50+ year career, Miyazaki earned himself a place among the all-time filmmaking greats, releasing some of the most beloved animated films ever made. From epics like Spirited Away to smaller coming-of-age films like Kiki's Delivery Service, the filmmaker proved himself capable of using fairytale-inspired stories as vehicles to wrestle with some surprisingly grounded human emotions and ideas.

That’s especially true for Castle in the Sky, a 1986 animated adventure film written and directed by Miyazaki, which sees the legendary animator leaning further into the sci-fi genre than he did in many of his other films. The result is an adventure that’s just as whimsical and wondrous as anything the filmmaker ever made and one that tackles many of the same themes he would further explore in films like Princess Mononoke and Howl’s Moving Castle.

It’s available to stream now on HBO Max. Here’s why you need to seek it out ASAP.

A young girl plummets from the sky with no sign of help or rescue in sight until the blue pendant necklace that hangs from her neck begins to glow. Gradually, the girl’s fall begins to slow, and she is caught and rescued by a young boy who offers her shelter and protection.

Later, the two discover that the pendant is made from the same material that’s said to be the foundation of a legendary floating city known as “Laputa.” Unfortunately for them, they’re not the only ones interested in the mystery of Laputa and are forced to go on the run from government agents and pirates intent on kidnapping the girl and her pendant to discover the city’s location and take its untold power for themselves.

That’s the basic premise of Castle in the Sky, and just like he does in all of his films, Miyazaki uses the fairytale elements of its story and characters (the princess with an untold past, a hidden city holding unknown treasures within its walls) to explore issues that are very much present in our real world. In the case of Castle in the Sky, the filmmaker grapples with the dangers of technological progression — with Laputa representing different things to each of the film’s various characters.

For the film’s young heroes, the city is a way to connect more deeply with their ancestors and family histories. Yet, to the government agents in pursuit of them, it’s just a weapon with the potential to make them the most powerful beings on the planet. For the film’s third set of power players, a wacky and greedy family of sky pirates, it’s the city’s rumored, supposedly priceless treasures that interest them.

By giving each of his characters their own distinct points of view and reasons for seeking out Laputa, Miyazaki populates Castle in the Sky with an overwhelming number of memorable and distinct characters. Each is fully realized and three-dimensional in their own ways.

It’s when their paths all cross in the film’s climactic, stunningly subversive third act that Miyazaki not only justifies each of their roles in the film but also uses them to ultimately bring home the environmentalist themes at the heart of his story. While the filmmaker delivers in his climax on all the expected bombast and action set up by Castle in the Sky’s first two acts, he does so in a way that’s both genuinely surprising and commendable.

The film’s climactic explosions and deaths become moments of horror, not excitement or catharsis, as Miyazaki fills his otherwise colorful and peaceful world with black and red fire and dark, cold steel. As a result, we end up feeling the destructive impact of war, greed, and ambition in a way that is both surprisingly dark for an animated film and perfectly in keeping with the film’s central themes.

Part of the joy of watching a Hayao Miyazaki film is getting to see the moments in which the filmmaker allows both us and his characters to soak in the beauty of their worlds. There are more than a few moments like this in Castle in the Sky. The film is full of reverence for the natural world that has only ever been matched by a select few other animated and live-action films.

It’s a feeling that is strangely unique to Miyazaki’s films, and in Castle in the Sky, he uses it just as devastatingly as he does in many of the classics that followed it. But despite how impressive many of his later films are, Castle in the Sky is still one of his very best, which means it’s also one of cinema’s best movies — period.

Castle in the Sky is available to stream now on HBO Max.