In 1925, the British explorer Percy Fawcett disappeared. He and his son had ventured into the Amazon to search for a lost city, which Fawcett named "Z," that was said to have once had incredible wealth. A distinguished cartographer, Fawcett had made his name creating maps of the uncharted Amazon, and, like anyone who is driven to explore, he wanted to find the place that could not be found. Inspired both by British legend and his experience in the Amazon, he became convinced of this lost city, an Atlantis on land, and he embarked on three separate journeys to find it. He was forced to abandon the first two prematurely, and the third one took him and his son away.

Fawcett was also a little mad. You have to be, to leave a young family (Fawcett was married and about to have his second child when he took his first expedition to map an area between Bolivia and Brazil) for the jungle, for skin rashes and blistering heat and clothes torn and hardened by sweat. And that is what The Lost City of Z, a film depicting Fawcett's quest to find his fabled city, is about--madness, obsession, the echo in the back of your head that won't stop.

This is tricky, given the film's setting. There is a certain amount of baggage that comes with an Edwardian-era period piece--droll, nearly-whispered line readings, ornate clothing, dusty rooms with the shades drawn low. The quantity of these aesthetic signatures can be enough to suffocate any signs of life. You risk reducing your film to a collection of empty signals.

But James Gray, the film's director and writer (he adapted his screenplay from the book by David Grann), is more interested in what is going on inside of Fawcett, that aching, blinding desire to prove that his dreams are real. This is Gray's greatest strength--the ability to ground a film in a character's interior life. Though he works within traditional narrative structures, he understands that a film is not just a string of events, but a series of sounds, images, and sensations. You can write out the plot on a piece of paper; you can't do the same with the radiating, distorting heat of the jungle, or the dirt and blood from a trench in wartime. (Between his expeditions, Fawcett serves in World War I.) These are matters for the big screen. They're better shown than told.

So, Gray does what great filmmakers do: He takes what he needs from the traditional structures of Hollywood cinema and ignores the rest. Early on, we learn that Fawcett has a raw talent and passion that have yet to be paired with a mission that matches his ambitions. But he has a wife, a young child, and another on the way. Any attempt to satisfy his urge for renown will separate him from his family for multiple years. This is all you need to understand the rest of the film.

There is the expectation in a Hollywood film that any narrative implication will receive an explanation. When Fawcett discovers his assistant, Henry Costin (played wonderfully by Robert Pattinson,) is drunk at their first meeting, you sense a budding storyline, possibly a flashback explaining why Costin is driven to drink. When Fawcett and Nina, his wife, fight before his second attempt to find Z, you expect that the next twenty minutes will be devoted to their marriage. But Gray presses forward. When the traditions of cinematic storytelling suggest an unnecessary diversion, Gray wisely ignores it, because he understands where this story lives--in the jungle, when poisoned arrows are shot from the trees, in the moments when Fawcett doesn't know whether he will gain the trust of an indigenous tribe or be killed by them.

In this way, Gray is a sensual filmmaker in the most literal sense. He recognises that the life is in the frame, not in what the frame implies. This is his second collaboration with cinematographer Darius Khondji, and again, Khondji and Gray construct images with the elegance of a painter or nature photographer. They know how to catch light at just the right angle, where to focus a lens, how to use distance to create compelling proportions.

But there are many visual stylists who forget that cinema is an active medium, that the images and the characters inside them must move and feel. This is why Joaquin Phoenix (who had starred in Gray's previous four films) was a perfect collaborator for Gray. No modern actor is better suited to raging passion and the streaks of insanity that fuel it. Phoenix, in his words, body, and face, can turn a character inside out and show what haunts him, while suggesting what is still hidden and what might happen if it comes to the surface. To watch Phoenix is to watch a raw nerve become tangled.

Charlie Hunnam, who plays Fawcett, is not that kind of actor. There are things he does well--composure, intensity, resolve--but he does not have that glimmer of madness in him, that raw, combustible material that might explode at any moment. He only unlocks half of Fawcett, the half that gave him the strength to remain calm in a hostile environment. On screen, Hunnam has weight, but no volatility.

Robert Pattinson has both. He gives an excellent, slightly loopy performance which matches the film in tone and rhythm. Where Hunnam is a fixed point, Pattinson moves in harmony with Gray. At any moment, you can sense a vivid inner life that can't quite square with his reserved exterior. You sense secrets that want to be let out. Angus Macfadyen, who plays James Murray, a famed explorer whose mettle does not match his stature, finds a similar gear. Murray is an aristocrat who wants to be a rugged man of action, or rather, wants to be known as one. When he is exhausted, he becomes theatrical in his self-pity; he wants someone to recognise and admire his labour. When that is not possible, he crumbles. There is a looseness in Macfadyen and Pattinson that Hunnam can't match.

But even when Hunnam can't sell you on Fawcett's madness, Gray can. There is clarity in the faces and expressions he puts on screen, but also in the textures of the jungle, its density and heat, and the way a river can seem to extend into eternity. Like those in Apocalypse Now or The Master, these are pretty images infused with human passions, and they're what you take with you when you leave the theater, the feeling that all these scenic locations mean something to someone, light up his senses and imagination.