‘The Lost City of Z’ a very mesmerizing adventure

“He’s been rather unfortunate in his choice of ancestors,” is how one character explains Percy Fawcett’s predicament early in “The Lost City of Z,” based on David Grann’s nonfiction book. Fawcett (Charlie Hunnam) is a British officer but decoration has eluded him, and his deceased, disgraced father has soiled his name.

Though craving action, he’s assigned in 1906 on a map-making mission to the “blank spaces” of Bolivia where the British are meant to act as “referees” in a territory dispute with Brazil. The expedition into the Amazon jungles soon fills him with a romantic sense of exploration (his wife, Nina, played by Sienna Miller, reads him Kipling’s “The Explorer”), and he travels across the Atlantic in search of glory and redemption. Success, he’s told, would change his lot “considerably.”

On the boat to South America, Fawcett meets his aide-de-camp, Henry Costin (an excellent, heavily bearded Robert Pattinson), who initially eyes his leader warily. “You might be a little too English for this jungle,” he says as they step through flies and snakes.

They and their small team travel up a river and it immediately feels as though “The Lost City of Z” has swum into the currents of Werner Herzog’s “Aguirre, the Wrath of God” and “Fitzcarraldo” and Francis Ford Coppola’s “Apocalypse Now.” The ominous notes are many: a glassy-eyed rubber baron (Franco Nero) whose business the British are there to protect; a native guide who warns that the river “is always danger”; the onset of hunger among the thinning crew.

But while Fawcett’s journey is grueling and frightful, he finds not madness in the jungle but wonder. His grandiose notions aren’t humbled in the Amazon, they’re elevated. Gray’s camera, too, stays composed, and he leads his epic in a more sprawling direction.

Fawcett believed that he found deep in the Amazon evidence of an ancient civilization. Upon his return to London, he’s hailed as a hero. (Made a celebrity by his exploits, the Stetson-wearing Fawcett was a forerunner to Indiana Jones.) But his claim of a lost city and a civilization older than England’s is mocked. He’s urged not to raise the stature of “the savage.”

The jungle becomes Fawcett’s compulsion, and, to the detriment of all else, he swells with ambition. It’s a huge step up for the magnetic Hunnam, who nevertheless struggles to find much but wide-eyed idealism behind Fawcett’s adventuring. More trips follow, as does World War I, but the tension that moves to the fore in “The Lost City of Z” is over the sacrifices necessitated by his dreams. With every journey taking years, he’s a stranger to his children. (Future “Spider-man” Tom Holland pivotally plays the eldest son Jack).

It isn’t just Fawcett’s sacrifices, either. Nina might have the appearance and size of a traditional secondary spouse role, but she’s beautifully performed by Miller as a proudly independent woman left to raise their children alone. Her own aspirations are obliterated. Colonialism is embedded in Fawcett’s story, but Gray has keenly sought out its quieter, unsung tragedies.

“The Lost City of Z” may, like early films by Gray, leave some thirsting for more swashbuckling adventure. But if you let the ebb and flow of the Fawcetts’ lives drift over you, the movie is a wellspring.

“The Lost City of Z,” a Bleecker Street, Amazon Studios release, is rated PG-13 by the Motion Picture Association of America for “violence, disturbing images, brief strong language and some nudity.” Running time: 140 minutes. Three and a half stars out of four.