Television shows are about the journey, not the destination. Train rides are the opposite; with the exception of some luxury lines, most people board trains with the sole intention of getting where they need to go.

Snowpierceris a TV show about a train that has no destination. Its passengers are the last vestiges of humanity, saved and doomed by their passage on an eternally running train that allows them to survive while the Earth falls into a permanent ice age.

As a show, Snowpierceraccidentally adopts the meaninglessness of a train without a destination and fails to find the momentum to sustain its journey. Its concept is solid, its performances are admirable, but neither of those can hide the fact that Snowpiercertakes too long to get good, and by the time anything interesting happens, the ride is already over.

Snowpiercersuffers from having both too much and not enough time to develop all of its ideas into a coherent story. The two-hour Bong Joon Ho film upon which it is based (and the comic series by Jacques Lob and Jean-Marc Rochette it was based on in turn) was the relatively straightforward tale of the Tail class's revolution, but the show’s 10-episode runtime gives the show space to explore what life is like for low-, middle-, and upper-class citizens on the train as well. As a result, Snowpiercer is packed with characters from all walks of life with varying motives that occasionally dovetail, but largely feel separate from each other even as the story brings them closer together in the show’s final episodes.

Some of those disparate elements are interesting by themselves, but often they fall short of their potential. The murder mystery that sparks the events of the show is compelling at the start but is resolved too quickly (and bizarrely) to contribute lasting tension. One young character’s rise through the ranks of the train is a solid storyline that falters when his subplot winds up serving another, far less interesting character’s motives. The central plot of the Tail class’ revolution winds up being the most satisfying element of the show and involves two of the season’s best twists, but the best parts of that story don’t come through until the last third of Season 1.

Other elements are simply odd and feel so out of place that their inclusion smacks of the show’s documented history of script rewrites and reshoots. Most of these revolve around the addition of the Night Car, Snowpiercer’s all-class “safety zone” car that serves as part nightclub, part appointment-only hypnosis therapy salon. To say too much about how the Night Car fits in with the rest of the story would be a spoiler; it is also beyond the powers of any watcher to justify why many of its scenes even need to be there. There’s a terrible live performance of Frank Ocean’s “Bad Religion” in there that is baffling, to say the least.

What keeps Snowpiercerchugging along are its performances and the hope that something cool might happen later on. Of those performances, Daveed Diggs is excellent as Andre, a “tailie” and former homicide detective who is dragged from the darkness of the caboose and thrust into the light of the train’s thousand other cars. Diggs gives Andre the suave humor of a seasoned television detective and the barely concealed fury of a revolutionary — one scene where he plays “good cop/bad cop” with an entire restaurant of first class passengers is an unexpectedly hilarious testament to his charisma.

Jennifer Connelly is also great as Melanie, the train’s head of hospitality with an entire suitcase full of secrets. Her character is the show’s most complex, as she is responsible for upholding Snowpiercer’s class system while clearly showing sympathy for the plight of its poorer citizens, and her icy exterior mirrors the deep freeze that surrounds the train at all times. Her foil is Ruth Wardell (Alison Wright), her second-in-command at hospitality who worships Snowpiercer’s engineer Mr. Wilford and fully believes in the glory of the eternal engine. Wright plays Ruth as a clipped, grating zealot, whose wide-eyed horror at the idea of changing the way things work on the train make her a perfect hyper-capitalist villain.

Snowpiercer’s slow pace could have made the show a miss. However, it must be said that the episodes leading up to the finale are fantastic. It’s clear that the show is not intended to be a limited series, and the jaw-dropping “holy crap” moments that end its first season are exciting enough to warrant some hype for a potential Season 2. The ending is so good that Season 1 feels like a prequel to the realprequel, leaving its audience wondering why the show couldn’t drop a few of its big finale twists earlier in the season.

It’s frustrating to see any show bank on the idea that next season will be better than the first, but the possibilities for the future of Snowpiercerare far more interesting than anything they’ve shown so far. Not everyone will get on board with Snowpiercer, but those who grab their tickets now might be in for a great ride...later.

Snowpiercer premieres Sunday, May 17 on TNT.