TNT’s adaptation of the French comic and Bong Joon-ho film struggles to stretch its high-concept premise across an entire series.

The TV version of Bong Joon-ho’s 2013 sci-fi thriller Snowpiercer (adapted from the French comic Le Transperceneige) has taken a long time to depart. In one form or another, it’s been in the works since 2015, starting with a Scott Derrickson-directed pilot written by Josh Friedman to run on TNT; shortly after that, Friedman was taken off the project due to “creative differences” and the pilot was heavily reworked and reshot by James Hawes, with Orphan Black creator Graeme Manson taking over as showrunner. It was even set to switch networks to TBS, before being flipped back to TNT just in time for the show’s release.

It’s a herky-jerky ride with a lot of switched tracks, which feels like the perfect metaphor for Snowpiercer‘s first season as a whole. Now the final product is here, sanded down to a basic-cable friendly format and stretched out to a shadow of its former self. It’s still reasonably exciting and inventive, but that essential spark that made the Bong film so novel just isn’t there.

Unlike the Bong film, which is a straightforward tail-to-tip class war among the residents of a perpetually-moving train carrying the last remnants of humanity along a flash-frozen Earth, TNT’s Snowpiercer lingers a bit more on its class tensions. The train’s class system is given an inch more elaboration: there are the first-class passengers in the front, the idle rich who complain about customer service in their cushy accommodations, the second-class who live in relative comfort, and the working-class who run the systems and the brothel/nightclub Night Car. And there are the ‘tailies,’ the impoverished hordes of refugees who stormed the train in the early days of the freeze and who now live in cramped, cell-like quarters in the back. All of them, of course, are ultimately beholden to the whims of the train’s creator, the unseen, mysterious Mr. Wilford.

One such tailie is Andre Layton (Daveed Diggs), a former Chicago homicide detective slowly fomenting a class revolution aboard the train. But he’s snatched out of the tail cars unceremoniously by head of first-class hospitality (and Wilford mouthpiece) Melanie Cavill (Jennifer Connelly) to perform a job only he can do: solve a murder. He agrees if only to gain enough intel on the front cars to fuel his revolution; however, he finds himself wrapped up in secrets and conspiracies that threaten to destroy the entire ecosystem of humanity’s last hope.

Like many network and cable shows adapting high-concept sci-fi properties, Snowpiercer feels frustratingly whittled down into a police procedural. It happened with Limitless, Frequency and countless others, and now Snowpiercer, which spends much of its first season on a whodunit that ultimately feels like a distraction from the class warfare that fuels the show in the first place. Granted, it’s a necessary conceit to give the show the variety it needs to survive: Layton’s presence is a fly in the ointment for not just the wealthy one-percenters at the front, but his former tailie compatriots who think he may have sold them out. But by the time the murder is solved, and the fallout from the event comes and goes, the event ends up feeling perfunctory, and the rest of the show chugs along apace.

It doesn’t help that the show’s basic cable budget leads to some necessary limitations in the look of the show. They manage some inventive stuff considering; John Grillo‘s cinematography adroitly matches the Bong film in its grimy, ink-black tail section, while playing around with some neo-noir neon for the nightclub-like Night Car. The visual effects are pretty solid to boot, especially when we do get to see the frozen world beyond, and Snowpiercer trudging along the snowy wastes. But you can feel the visual imagination of the premise (and the designers) strain against the financial constraints of a concept this bold condensed into ten hourlong episodes.

The biggest problem with Snowpiercer is that the broadness of the class metaphor simply can’t sustain itself over the length and breadth of the series. The rigid haves vs. have-nots structure is a neat symbol for a comic book or a feature-length film, but milking such a limiting conceit over an entire show leads to some highly diminishing returns. They try to bulk this out with a large cast (many of whom start out each episode with an on-the-nose monologue about the nihilistic life on the train, “1001 cars long”), but there’s so much ground to cover we don’t get to know many of them that well.

The biggest problem with Snowpiercer is that the broadness of the class metaphor simply can’t sustain itself over the length and breadth of the series.

Apart from Diggs, who does a lot of the plot’s heavy lifting with his hard-eyed determination, and Connelly’s wily cunning, most of the other performers don’t leave much of an impression. The Americans‘ Allison Wright is occasionally fun as the Tilda Swinton analogue from the film, but characters like Layton’s brakeman ‘partner’ Till (Mickey Sumner) and Katie McGuinness‘ stalwart tailie Josie aren’t given much time to flesh out their relatively stock personages. Instead, we’ve got dozens of faces to keep and lose track of, many of them running in place against one contrivance after another — from worker negotiations for the third-class passengers to making death-defying repairs to the train.

Simply put, the one-track mind of Snowpiercer is both its greatest asset and its greatest detriment. In a time when we’re more visibly disillusioned with the rich than ever, the notion of exploring the way class divisions could literally result in the end of humanity is a tempting one, especially in a premise this strange. But the show is burdened with extending a simple, goofy idea to ten-plus hours of television, and it can’t quite fill the time well enough to justify it.

One wonders if there were bolder, stranger choices made in the original Derrickson-Friedman version that could have given this a stronger start pulling out of the station. The show has its high points — Connelly is absolutely electric, and the season finale sets up some intriguing mysteries for the already-confirmed second season. But Snowpiercer has a way to go before it gets back on track.

Snowpiercer embarks on TNT Sundays starting May 17th.

Snowpiercer Trailer: