GODALMING, England — Entirely covered by earth, only his face visible, Ralph Fiennes lay patiently in the ground. Simon Stone, the director of the new Netflix drama, “The Dig,” peered at a monitor, then nodded. “Let’s go,” he said. Fiennes shut his eyes, and a waiting crew poured soil over his head, burying him completely. Carey Mulligan dashed forward, panic-stricken, and began to frantically scrabble at the ground.

“I wasn’t really acting; that was scary,” she said with a shaky laugh when the scene was over and Fiennes, looking unbothered, was being dusted down and getting ready to do it all over again.

It is one of the few overtly dramatic scenes in “The Dig,” the true story of one of the most important archaeological finds of the past century: the discovery, in 1939, of a sixth-century Anglo-Saxon burial ship at Sutton Hoo, a small area along a riverbank in Suffolk, on Britain’s east coast.

The land belonged to Edith Pretty (Mulligan), a wealthy but ailing widow with a keen interest in archaeology, who had long been curious about the raised mounds in her fields. The film begins as she hires a laconic local man, Basil Brown (Fiennes) a self-taught excavator, to investigate as World War II looms.

Both Pretty and Brown were convinced there was something to discover; neither imagined it would be an archaeological find that would change notions of early European history. The ship, which had been hauled from the nearby river, was effectively a burial chamber, with its illustrious occupant bedecked in finery and provided with money, food, household goods and art for his journey to another world. (Pretty donated it all to the British Museum.)

“This changes everything!” exults Charles Phillips (Ken Stott), the Cambridge academic who is charged with taking over the dig when news of the find breaks. “These people weren’t just marauding barterers. They had culture! They had art! They had money!”

“The Dig,” out Jan. 29, was adapted by Moira Buffini (“Harlots”) from John Preston’s 2007 novel of the same name. Preston discovered that his aunt, Peggy Piggott (played in the movie by Lily James), had been involved in the excavation. and his subsequent research, he said in an interview, revealed “a treasure story for grown-ups.” It’s a tale of an unlikely kinship between Brown and Pretty across barriers of class and gender, and of the unearthing of a magnificent ancient civilization just as the world headed toward the devastation of war.

Stone, well known in Europe as a theater and opera director who has radically reimagined canonical works like “Yerma” and “La Traviata,” spent his early years in Britain, but moved back with his family to their native Australia at 12. “The Dig” is his second film (after “The Daughter”), and its period gentleness, rootedness in time and place and slow pace are a significant departure from much of his previous work.

But Gabrielle Tana, who produced the film, said that as soon as she met Stone, she knew he was the right director. “Various directors had been associated with the project, and for one reason or another hadn’t worked out,” she said. Stone “talked about how essential it is to maintain the relics and artifacts of our civilization so that we don’t forget our past. I had to hound him; he wanted to do it, but he always has five operas and six plays on the go.”

She succeeded, and critics have applauded his vision of the story. “Stone proves to be an unexpectedly ideal match for the material — like Peter Weir and Warwick Thornton, he has a distinctively Australian feel for a landscape’s mystery and strangeness and scenes that could easily have been postcard-pretty have a slightly dreamlike texture that catches you off-guard,” Robbie Collin wrote in The Telegraph.

In a telephone interview from Berlin, Stone said that he had been drawn to “how unconventional the story was in its packaging, how unsexy.”

“I was fascinated by the challenge of making these characters, constrained by their time and personalities,” he added, “as full of life and energy as any contemporary character I would direct in a play.”

To that end, Stone said, he tried to keep the actors “very unrehearsed, very free, very spontaneous.” The actors, who were often asked to improvise lines after their scripted exchanges had ended, didn’t know where other performers would be standing or moving in a scene; the director of photography, Mike Eley, wasn’t told where characters would be placed. Sometimes, Stone said, these methods “go horribly wrong, but more often it leads to a kind of spontaneity that contradicts our ideas about mannered period drama.”

Fiennes, who was born in Suffolk and has regularly returned to the area throughout his life, said that he had “a particularly strong sense of wanting to get it right” when it came to Basil’s accent and mannerisms. He engaged a local coach and cycled around Suffolk on an old-fashioned bicycle, clad in the heavy fabrics that Basil would have worn. “You see the land differently at that pace,” he said. “It chimed with my sense of Basil; he could read the land and the soil, where it plateaus and changes, where it dips, what its contours are.”

But for all the immersion in authentic character detail, Fiennes said that he had loved the freedom that Stone encouraged in his actors. “I am very trained to focus on the text, and I loved having the permission to run away with it,” he said. “There is an energy in that which hasn’t been repeated and rehearsed.”

The central relationship between Edith and Basil is unusual in a film, Mulligan pointed out, because it not romantic “but a simple meeting of minds, a kinship.” Stone said that he had eliminated even the vestiges of intimacy that were in earlier drafts of the script “because it undermined the radical nature of their relationship.” Basil, restricted by his social class, meets Edith, restricted by her gender, but they share a similarity of spirit. “I love the libido of the mind, which is harder to make as exciting as the libido of the body,” Stone said.

(The sexual tension in the movie is dutifully provided by the attraction between James’s unhappily married Peggy, and Rory Lomax, Edith Pretty’s dashing young cousin, played by Johnny Flynn.)

The logistics of depicting the dig itself were daunting, said the production designer, Maria Djurkovic. “We had to physically create the mounds, a virgin landscape, with tons of soil and plantings, then show the process to the reveal of this 100-foot Saxon ship in the ground,” she said. Her strategy was to work backward. “I suggested we start the shoot with the reveal of the ship, then pile earth over it and go back in the story to the moment when Basil sticks a shovel into the earth for the first time.”

That moment, said Stone, happens just as the encroaching war brings a pervasive sense of uncertainty about the future. It’s a feeling, he added, far more real to us in the midst of a pandemic than it has been for many decades. “I think we are all waking up to the arrogance of our assumptions that there won’t be these kinds of world-changing moments in our lifetimes,” he said.

But the shovel hitting the earth reminds us, as Basil points out, that humans are part of something continuous. In Stone’s words: “Digging in the earth while the skies are filled with planes may seem like an act of folly. In fact, it’s an act of preservation.”