Charlie Hunnam and Tom Holland set off on a harrowing journey into the Amazon in the teaser trailer for "The Lost City Z."

Based on David Grann's nonfiction bestseller, the film tells the true story of British explorer Percy Fawcett (Hunnam), who in 1925 disappeared into the Amazon with his son (Holland) in search of an ancient lost city.

Directed by James Gray ("We Own the Night"), "The Lost City of Z" debuted in October at the New York Film Festival, and has earned mostly favorable reviews.

Based on author David Grann’s nonfiction bestseller, THE LOST CITY OF Z tells the incredible true story of British explorer Percy Fawcett (Charlie Hunnam), who journeys into the Amazon at the dawn of the 20th century and discovers evidence of a previously unknown, advanced civilization that may have once inhabited the region. Despite being ridiculed by the scientific establishment who regard indigenous populations as “savages,” the determined Fawcett – supported by his devoted wife (Sienna Miller), son (Tom Holland) and aide de camp (Robert Pattinson) – returns time and again to his beloved jungle in an attempt to prove his case, culminating in his mysterious disappearance in 1925. An epically-scaled tale of courage and obsession, told in Gray’s classic filmmaking style, THE LOST CITY OF Z is a stirring tribute to the exploratory spirit and those individuals driven to achieve greatness at any cost.

Also starring Robert Pattinson as fellow explorer Henry Costlin and Sienna Miller as Fawcett's wife Nina Fawcett, "The Lost City of Z" arrives in U.S. theaters in April.