Slate's Dana Stevens and Forrest Wickman discuss Snowpiercer. WARNING: This podcast is meant to be heard AFTER you've seen the movie.​

Snowpiercer, the fifth feature by the visionary South Korean director Bong Joon-Ho (Mother, The Host), is a lot of movie to take in at once. Very loosely adapted by Bong and co-screenwriter Kelly Masterson (Before the Devil Knows You’re Dead) from a French graphic novel set on a frozen future Earth, it’s without question the director’s grandest-scaled and most technically ambitious work to date. Snowpiercer takes Bong’s habitual disregard for genre boundaries to a new level, using a cunningly designed Dickensian steampunk dystopia as the setting for a bleak political allegory about environmental destruction and widening income inequality. Nor does Snowpiercer skimp on the elaborately choreographed ax battles, goofy comic pratfalls, or tear-drenched heroes’ farewells—all aboard a perpetually racing train that, in Bong’s radical re-envisioning of the original story, circles the Earth exactly one time per year, carrying what remains of humanity.

Seventeen years before the film begins in 2031, a manmade environmental disaster—apparently the result of an attempt to counteract the effects of global warming—has rendered the Earth so cold as to be inhospitable to all life. Those few lucky enough to have survived the big freeze have been herded onto the world-circling train, which is divided into strictly hierarchized social castes kept separate by armed guards. Members of the elite live in obscene luxury at the front of the train, while the filthy, semi-starved masses live in close-packed squalor in the tail. The cars in between contain a whole functioning ecosystem, complete with orange groves, self-sustaining aquariums, and a refrigerated butcher car—all of which will come as news to the beaten and oppressed denizens of the tail, who are stacked in windowless bunkrooms and fed only slabs of gooey black gel known as “protein blocks.”

Snowpiercer tells the story of a rebellion led by tail-dweller Curtis (Chris Evans, unrecognizable in a black beard and fatigue-creased eyes), who, counseled by his elderly mentor Gilliam (John Hurt), attempts to lead a charge on the front of the train to take control of the engine. Curtis’ co-conspirators include his loyal sidekick Edgar (Jamie Bell), who’s young enough not to remember life before the disaster, and Tanya (Octavia Spencer), whose 5-year-old son is among a group of children abducted from the back of the train for mysterious purposes.

As they progress forward car by car through the train—each transition marked by a bloody battle—Curtis’ raggedy homegrown militia eventually joins forces with a Korean security expert, Namgoong Min-soo (Song Kang-ho, whose contained, offbeat screen presence has featured in three of Bong’s five films). Nam, who carries a high-tech device that instantly translates his spoken Korean into English, shares little of his fellow tail-dwellers’ revolutionary fervor, but he agrees to help them fight their way to the front of the train in exchange for regular hits of Kronol, an industrial waste product that can be sniffed as a drug. Even more pitifully addicted to Kronol is Nam’s teenage daughter Yona (Ko Ah-sung, who also played Song’s imperiled daughter in Bong’s hit 2006 monster movie The Host).

Of course, the multistage takeover of a moving train is a hard maneuver to keep secret for long, and soon the creator and maintainer of “the sacred engine”—a seldom seen, much-mythologized figure known only as Wilford—is sending back a representative to quell the uprising: the snobbish, cowardly Minister Mason (Tilda Swinton, thoroughly enjoying her Yorkshire accent, piggish prosthetic nose, and memorably unsightly false teeth). Mason takes a midlevel bureaucrat’s sadistic pleasure in carrying out her nasty tasks of torture and public shaming, but there are hints she may be willing to betray her boss and abet the rebels if it’s her life on the line.

Unless you have a huge appetite for gnarly fight sequences, this seizing-control-of-the-train section gets a bit long and structure-less, though I will say this for Bong: His action scenes never build or resolve according to familiar Hollywood formulas. Any character, no matter how narratively important or beloved, can get the ax (often literally) at any time, which gives the battle scenes a palpable sense of emotional as well as physical suspense.   

After the rebels—what’s left of them—finally make their way to the first-class passenger cars, the director (and his ingenious DP and production designer, Hong Kyung-pyo and Ondrej Nekvasil) have a field day replacing the grubby, dim look of the early scenes with an ever-shifting succession of visually splashy built environments. In the crayon-box-colored elementary-school car, a chirpy pregnant teacher (Alison Pill) indoctrinates her pupils with propaganda about their glorious leader, Wilford. Other specialty cars are devoted to a swank futuristic nightclub, a Dantesque Kronol-sniffing den, and a sushi bar where our bloodstained, battle-dazed revolutionaries find themselves sitting down for a surreal snack.

I felt a slight letdown in Snowpiercer’s final scenes, when the mission’s few survivors arrive at the engine room to discover the true identity of the storied Wilford (about whom I’ll only say that he’s played with twinkly menace by Ed Harris). It’s here that the film’s subterranean critique of capitalist depravity suddenly gets a lot more … terranean, and more than a little heavy-handed. But the go-for-broke action climax, involving a homemade bomb, a churning engine, an inexplicably unstoppable assassin (played without a word of dialogue by the Romanian actor Vlad Ivanov), and a hell of a lot of snow, is heart-stopping. Who cares that the digital exterior shots of the hurtling train aren’t up to the animation standard of a Michael Bay blockbuster? Snowpiercer is its own strange, special thing, a movie that seems to have been sent back to us from some distant alternate future where grandiose summer action movies can also be lovingly crafted, thematically ambitious works of art. Let’s keep pushing ahead, one train car at a time, until we get there.