Silence, the new film by Martin Scorsese, opens with almost as literal a vision of Hell as one could imagine. The year is 1633; the place, a craggy, volcanic expanse near Nagasaki called Unzen. Through the sulphur fumes and scalding vapor, we see European men, their hands tied, being led by Japanese soldiers to the boiling springs that dot the landscape. Their robes are parted and searing water poured on their skin. In voiceover, it is explained that the ladles used are perforated such that each individual drop may strike the skin “like a burning coal.” The springs themselves are called, aptly enough, jigoku, or “hells.”

The man narrating this excruciating torture is Father Cristóvão Ferreira (Liam Neeson), a Jesuit missionary. The victims, who number in the dozens, are his fellow Catholic priests. Christianity has been outlawed as a threat to Japanese culture and it is being burned out of the country in the most direct manner available.

Father Ferreira’s observations are committed to a letter, and it is in that context that we hear them again. It is now 1640, seven years after the horrors he recounted, and a senior Jesuit (Ciarán Hinds) is reading the letter to two young priests who were once Ferreira’s pupils, Sebastião Rodrigues (Andrew Garfield) and Francisco Garupe (Adam Driver). The elder priest also informs them that Ferreira subsequently disappeared and is rumored to have “apostatized”—that is, renounced God.

Rodrigues and Garupe refuse to believe this of their beloved mentor, and they vow to find him and dispel the slander. Their superior accedes to their mission, though he reminds them of the extraordinary danger they will face from the moment they set foot in Japan: “You will be the last two priests ever sent.”

Silence is based on the celebrated 1966 novel of the same name by Shūsaku Endō, and Scorsese has been vowing to bring it to the big screen ever since he first read the book in 1989. At the time, he was dealing with the blowback to his controversial The Last Temptation of Christ, and in Endō’s story of faith and doubt, he felt echoes of both his recent experience and his longtime relationship with the Church, of which he had once intended to become a priest.

Nearly 30 years in the making, Silence is a heartfelt and serious work. But through length and redundancy—both, no doubt, the product of Scorsese’s deep admiration for Endō—as well as an underwhelming central performance by Garfield, it ultimately falls short of its powerful ambitions.

The two priests, Rodrigues and Garupe, are smuggled into Japan by Kichijiro (Yōsuke Kubozuka), a fickle and intemperate drunk. (There is a noticeable echo of the legendary Toshiro Mifune in the performance.) There, they encounter a town populated by secret Christians, and their mission begins to shift, from finding and rescuing Ferreira to ministering to these devout peasants, who live in terror of discovery by the authorities. The Japan of these early scenes—conjured by the cinematographer Rodrigo Prieto—is a misery of rock and rain, in which mud-bound villages can hope for little more than not to be swept entirely out to sea.

Eventually, official “inquisitors” do come to the town in which the priests are hiding, and the two men are forced to split up. For the remainder of the film, we follow the journey of Rodrigues as he witnesses atrocities against his fellow Christians—crucifixions, drownings, a beheading—grapples with his own faith, and is himself captured. Most of all, he suffers from the apparent “silence” with which God answers his prayers.

The tradeoff repeatedly extended by the authorities to those suspected of Christian belief would seem a simple one. Just place one’s foot on a fumi-e, a small plaque bearing a likeness of Christ or the Virgin, and one will escape punishment and perhaps be freed. Refuse, and one will face torture or worse.

Many of the peasants questioned refuse to step on the fumi-e and suffer accordingly. But many are willing to make that concession—and are, in fact encouraged by Rodrigues to do so—in order to keep their lives. Among the latter is the priests’ initial guide, Kichijiro, whose continued vacillation between apostasy and confession makes him one of the film’s more infuriating and provocatively human figures.

As is no doubt apparent, Silence is not an easy film to watch, its 160-minute running time awash in images of pain and cruelty. But neither is it a mere cinematic exercise in physical endurance or the punishments of the flesh, such as Unbroken or even The Revenant. Scorsese is attempting something far more interesting: a portrait of the endurance of the soul.

It is not, after all, Rodrigues’s body that is being tormented, but those of the people around him. And it is made abundantly clear that it is within his power to make it stop if only he will himself apostatize. As the chief inquisitor, Inoue, cunningly played by Issey Ogata, explains: “We learned from our mistakes. Killing priests only makes them stronger.” Another interrogator puts it still more directly when Rodrigues insists that the victims around him “didn’t die for nothing.” “No,” he replies. “They died for you.”

But for all the torments they inflict, the Japanese inquisitors are no generic movie villains. They truly believe that Christianity is incompatible with the Japanese spirit, an alien pathogen imported by arrogant and incurious Europeans. And the film gives this case its due. It is notable, for instance, that none of the Jesuits we encounter speaks more than a tiny smattering of Japanese, but peasants and inquisitors alike manage to make themselves understood in Portuguese (rendered in the film as English). One of Rodrigues’s captors—played superbly by Tadanobu Asano—is fluent enough to function as a full-time translator.

Indeed, one of the chief weaknesses of Silence is that so many of the characters in orbit around Rodrigues convey more narrative gravity than he does himself: Asano’s translator, Ogata’s inquisitor, Kubozuka’s fickle Kichijiro, Driver’s Father Garupe, a village elder played by Yoshi Oida. Andrew Garfield is a fine actor, but his calling card has always been a kind of boyish ingenuousness, and here it is tested beyond its limits.

Garfield’s previous major role of the year, Hacksaw Ridge, is illustrative. In it, as in Silence, he plays a devout Christian—one who served as an Army medic in World War II and, despite his refusal to carry a firearm, rescued 75 of his gravely injured comrades from the battlefield. But in Hacksaw Ridge, this Christian spirit was emphatic, uplifting, a source of near-limitless strength. It was the solution to the problem at hand. In Silence, by contrast, Garfield faces the far heavier challenge of grappling with the possibility that it might be the problem. Far from saving lives, Rodrigues’s faith is costing them.

Scorsese does Garfield no favors by extending his protagonist’s torments to such extreme lengths. The film is full of moments that, for all their elegance and power, feel repetitive: yet another scene of peasants being commanded to step on the fumi-e; another brutal torture; another confrontation between Rodrigues and the inquisitors in which each side talks past the other—universal truth versus cultural difference—without success.

These philosophical disputes, too, rarely achieve the depth or richness for which one hopes. Late in the film it is suggested, intriguingly, that perhaps the Christian faith of the Japanese peasants isn’t really Christian at all, that due to a long-ago error of translation, they worship not the “Son,” but the “Sun.” Alas, Scorsese’s film is more interested in cataloguing Rodrigues’s ongoing spiritual anguishes than in pulling further on such theological threads.

It all comes to an end—though I should warn, there’s still a half-hour left—when Rodrigues finally completes his mission and learns the fate of his mentor, Father Ferreira. I will not reveal what he discovers, but I will say that it feels like a moment that could easily have taken place far earlier in the film.

Let there be no misunderstanding: Silence is an indisputably worthy film from one of our greatest living directors, one that searchingly tackles questions of faith and doubt and duty. The visuals supplied by Prieto are themselves worth the price of admission—the desperate peasants crawling up over the side of a boat, like pirates or mermen; a town abandoned to a community of feral cats; a sea cave that functions like a portal from one world to the next. Scorsese’s abiding passion and respect for his source material are everywhere in evidence. For once, perhaps, they are a little too great.