The Lost City of Z Charlie Hunnam, Sienna Miller, Robert Pattinson. Directed by James Gray. Opens Friday in select theaters.

The title of writer-director James Gray’s The Lost City of Z promises something a lot more fantastical than the movie delivers, and the dull restraint that Gray relies on is a poor substitute for all-out jungle madness. Based on David Grann’s book about the life of British explorer Percy Fawcett, Lost City follows Fawcett (Charlie Hunnam) over a 20-year period, during which he becomes increasingly obsessed with discovering a lost Amazon civilization that he dubs Z. A military officer with a mostly undistinguished career, Fawcett accepts his first assignment to South America in hopes of furthering his career prospects, but he eventually puts those prospects in jeopardy in his quest to find the roots of ancient civilization.

After a somewhat staid setup that establishes Fawcett’s home life (with a feisty but long-suffering wife played by Sienna Miller) and job dissatisfaction, the movie comes to life when he first enters the jungle, accompanied by his eccentric traveling companion Henry Costin (Robert Pattinson). But what could have been a journey of increasing madness along the lines of Werner Herzog’s Aguirre, the Wrath of God is instead measured and subdued, as Fawcett repeatedly returns to England when his funds and/or supplies run out, never fully succumbing to his obsessions. He makes several more trips over the course of the next two decades, and some of the jungle sequences are intense, particularly on the trip when Fawcett and his crew are accompanied by arrogant, ill-prepared financial backer James Murray (Angus Macfadyen).

But Gray’s style is calm and stately, a pastiche of classical filmmaking without much life to it. Hunnam, who’s two years younger than Fawcett was when he embarked on his first expedition, lacks both the maturity and the intensity for the role, and he never really burrows into Fawcett’s obsession. Cinematographer Darius Khondji ensures that the jungle scenes look great, conveying the harshness and density of Fawcett’s surroundings, but the characters are not nearly as vibrant. Gray (The Immigrant, We Own the Night) is a cult figure among cinephiles, especially in Europe, and his movies demonstrate a deep respect for old-school filmmaking. Unfortunately, like Lost City, they’re generally easier to admire than enjoy.