The fortuitous timing of having a series produced by and featuring newly minted Oscar-winner Robert Downey Jr. tumbles down a very strange rabbit hole in “The Sympathizer,” a darkly satirical look at the Vietnam War and its aftermath. Playing no less than four roles, Downey stands in for multiple ugly Americans, but the series descends into a narrative quagmire and, despite powerful moments, can’t consistently pull itself out.

Directed in part by acclaimed South Korean filmmaker Park Chan-wook (“Oldboy,” “Decision to Leave”), who oversees the show with writer Don McKellar, the seven-episode limited series is adapted from Viet Thanh Nguyen’s Pulitzer Prize-winning novel. Each episode begins with dated-looking credits that evoke the 1970s, a promising Quentin Tarantino-ish conceit that, given what follows, sets expectations too high.

Told in flashback, and frequently rewinding to fill in details, the story focuses on the Captain (Hoa Xuande), a half-Vietnamese, half-French officer of the secret police who has surreptitiously been working for the North Vietnamese against the American-backed government.

The Captain’s lineage, and his double life, are emblematic of a man torn in different directions, which includes his relationship with two inseparable friends (played by Duy Nguyen and Fred Nguyen Khan). As constructed, it’s a rather heavy-handed approximation of the fate Vietnam experienced in the pull of the war, which doesn’t make the Captain’s increasingly surreal arc any more compelling.

That’s because the protagonist is relating his story to a Vietnamese interrogator, recounting a journey that includes the fall of Saigon, fleeing the country – in what’s surely the show’s most harrowing sequence – and his curious adventures in the US.

As for Downey, his various guises include everything from a CIA agent to a crazed movie director, a device that proves every bit as gimmicky, and for the most part unnecessary, as that sounds. The net effect is less Peter Sellers in “Dr. Strangelove,” assuming that was the intent, than a means of maximizing the star’s presence without really heightening its impact.

The Captain’s travels also brings him into contact with an American coworker (Sandra Oh) whose experience dealing with their racist boss comes in handy, and in perhaps the strangest detour, onto a movie set where he serves as a technical consultant, subject to the whims of Downey’s aforementioned director and an insane method actor (David Duchovny).

“The Sympathizer” is hardly the first project to funnel the contradictions of the Vietnam War through an exaggerated lens (“Apocalypse Now” being a prime example), but except for a few bracing sequences the execution only clouds that vision. The high hurdle of balancing the satirical tone seems especially noteworthy coming on the heels of “The Regime,” another splashy HBO production that similarly proved too cute and coy for its own good.

Credit Downey with leveraging his commercial clout to champion such challenging material and attract a marquee international director to American television, but in the final analysis, “The Sympathizer” plays like the latest instance of indulging a star’s pet project.

While there’s an obvious rationale for that strategy in the attention-oriented realm of premium TV, given that the series doesn’t match the promise its high-profile elements would suggest, sympathy isn’t one of them.

“The Sympathizer” premieres April 14 at 9 p.m. ET on HBO, which, like CNN, is a unit of Warner Bros. Discovery.