It Was Always Going to Be Tricky to Adapt This Pulitzer-Winning Novel. HBO Mostly Pulls It Off.

“Wars never really die,” says a character in The Sympathizer, a new HBO series based on Viet Thanh Nguyen’s Pulitzer Prize–winning 2015 novel of the same title. “They just hold their breath.” Unlike the best-known American novels about the Vietnam War—Tim O’Brien’s The Things They Carried, Robert Stone’s Dog Soldiers, Karl Marlantes’ Matterhorn—The Sympathizer begins as the war concludes, with the fall of Saigon in 1975. But it’s not over for Nguyen’s main character, a man known only as the Captain. A spy for the communist North Vietnamese embedded in the entourage of a South Vietnamese general, he’s evacuated from his homeland and is under orders to continue his pretense of loyalty to the general so he can report back on the Vietnamese refugee community in 1970s Los Angeles.

Park Chan-wook and Don McKellar, co-showrunners on The Sympathizer, have mounted a stylish, smart, and sometimes surreal adaptation of a complex and self-reflective novel, although the series, which premieres Sunday, can’t always keep its dramatic footing. “I am a spy, a sleeper, a spook, a man of two faces,” the Captain (Hoa Xuande) announces at the beginning in voice-over, reading the text of his “confession,” written in a Vietnamese prison camp. He has a talent, or perhaps a curse: the ability to “see any issue from both sides.” He couldn’t forget about his own duality even if he wanted to, because other people keep remarking on the fact that he’s biracial—the son of a French priest and a poor teenage villager. A graduate of an American university pretending to support a regime he’s actually trying to overturn, the Captain is forever torn between loyalties so convoluted and tangled they often leave him paralyzed.

As fascinating as he is on the page, the Captain makes for a tricky on-screen protagonist. He’s not always sure what he wants, and even when he is, he’s rarely free to pursue it. “Still an aide-de-camp?” the general’s saucy, rebellious daughter (Vy Le) teases him when they are reunited in L.A. after their flight from Vietnam. He is. Forever beholden to older, powerful men, the Captain gets out of the refugee camp even before the general (Toan Le) and his wife (a regal Nguyen Cao Ky Duyen) do because one of his former professors—an American Orientalist—agrees to sponsor him. He seems relegated to the passive role of dutiful attaché, obeying orders from the general, or his communist handler back in Vietnam, or Claude, the CIA officer who served as the general’s primary contact with the American government.

That professor is played by an extravagantly swishy Robert Downey Jr. So is Claude. So is the square-jawed politician funneling money to the general’s delusional scheme to overthrow the new government back in Vietnam, and so is the volatile, gibberish-spouting film director who hires the Captain as a consultant on his Vietnam War movie. In all, Downey plays most of the major American characters in the series. At first, this choice registers as a sly inversion of the old “They all look alike” slur. Each of these men is grotesque in a different but very American way. The professor decorates his office with shoji screens and berates his Japanese American secretary (Sandra Oh) for not partaking of her own “culture.” (“I’m from Gardena,” she retorts. “No one asked JFK if he spoke Gaelic and ate potatoes every night.”) The film director throws baroque tantrums and keeps a live alligator in a glass case. The politician is pretty much what you’d expect. And the CIA agent wears white shoes and a spray tan and is breathtakingly, terrifyingly cynical.

A little bit of these caricatures goes a long way, and the series’ biggest flaw is the way it bogs down in the middle as it lingers over Downey’s scenery chewing. In Nguyen’s novel, the Captain’s sojourn through the movie business—a slicing satire of how American auteurs like Oliver Stone and Francis Ford Coppola depicted Vietnam and the Vietnamese—is one of the funniest parts of the book. In the series, it’s the bit I found myself impatiently waiting through, longing to escape Downey and return to the Vietnamese ensemble.

The Sympathizer succeeds wonderfully at making Vietnam feel like the center of the universe, as it is for all of the engaging characters in the series. America—with its horrid food, shabby cement-box apartment buildings, and abundance of rats and cockroaches—becomes a different kind of prison camp for the Captain and his countrymen, a shadow land of exile. In his fiction, Nguyen has satirized the dewy nostalgia of the celebrations of Vietnamese culture staged by expats in the U.S., but the series is kinder. In one scene, a cabaret singer’s plaintive reiteration of the name “Saigon” conveys a pang of homesickness so powerful it makes you want to hit the pause button and start searching for airline tickets to whatever city you once loved and somehow lost.

For the most part, though, the series shares the novel’s resistance to sentimentality and ideological simplicity. The copy of Graham Greene’s The Quiet American lying on the Captain’s desk in the first episode signals as much. “You don’t want to come home,” the Captain’s handler warns him when he begs to return from L.A. “I can no longer be disappointed,” a fellow spy tells him when he ignores that advice and goes back anyway. Like many people who set out to be on the right side of history, the Captain finds himself doing terrible things. In this, Nguyen’s narrator has never entirely made sense. His communism seems notional, more a reaction to Western imperialism than a genuine set of political convictions. Why has he sacrificed so much to this cause? What he most cares about are the two friends he swore allegiance to in boyhood, each now on opposite sides of the conflict, each fighting for good reasons.

Moral conundrums often don’t make for riveting cinema, and The Sympathizer leans heavily on the considerable charisma of its lead actor to hold its viewers. Xuande’s Captain starts out poised, even cocky, able to manage the personality flaws, dodgy values, and outrageous demands of his various mentors with grace. Eventually, the impossibility of his situation dismantles him, scenes that Xuande plays with wrenching vulnerability. It’s as if the Captain starts out in a Coen brothers movie and ends up in a George Orwell novel, an unenviable trajectory. He thought the war was over and that his side had won. But it turned out the war was only holding its breath.