Under a blood-red setting sun, an old man stumbles along, clutching his bloodied neck. Passersby discussing universal welfare see him and one man begins to offer help but turns away complaining of the old man’s foul stench. He returns to his friend and dismisses the elderly gentleman as homeless. “I was gonna help if he was hurt,” he shrugs. The old man shuffles to a wall within Seoul Station and collapses to the floor, blending in with the other vagrants.

So begins Seoul Station, Yeon Sang-ho’s animated prequel to his hit 2016 live-action horror film Train To Busan. As a zombie pandemic spreads in downtown Seoul, a handful of people fight tooth-and-nail to survive. The shift in medium accompanies a change in tone and depth for the film, though the undead-laden narrative remains the same. Those familiar with Yeon Sang-ho’s critically-acclaimed 2011 drama The King of Pigs will find the same level of deliberate critique and intimacy in his work that is seen in Seoul Station, and less of Train To Busan’s white-knuckle action.

While not operating at the breakneck pace of Train To Busan, Seoul Station expands upon the socio-political context of its predecessor. Yeon Sang-ho sets up themes of classism from the beginning and continues with the centralized role of the major players in the story, players that occupy the lower stratum of society. Hye-sun (voiced by Eun-kyung Shim), a former sex worker, and her boyfriend Ki-woong (Joon Lee), have come up short on the rent, and Ki-woong pimps her out to make ends meet. In their ensuing argument, they angrily part ways and get caught up in the mayhem emanating from the terminus at Seoul Station.

As a story centralized upon the human condition, it only makes sense that the humans themselves are fully realized and allowed to breathe. Sang-ho is intimately aware of this and gives every character a wide berth to allow motivations and fears (other than the hordes of the undead) to flourish in his screenplay. The character arcs occur not in their relationships with each other, but in their interactions with law enforcement and the rest of society at large. Local law enforcement’s failure to discern between the infected and the homeless population is at once blood-boiling and unsurprising; in Sang-ho’s story, the infection is not just epidemiological, it is societal. The contextual underpinnings are far more heavy-handed here; where Train To Busan had mild coughs of classism in the periphery of its conflicts, Seoul Station is a presentation of feverish cultural malaise.

Yeon Sang-ho deftly counterbalances the big-picture subtext with a concentration on a trio of protagonists and their small-scale struggles to survive. From Ki-woong and his burly companion arguing over strategy as they make their way through the streets to Hye-sun’s endearing conversation with an older man in the station itself, the scaled-down endeavors act to humanize a class of citizens that have been dehumanized by the population at large.

With such a deep focus on characterization, the decisions that the characters make are just as important as the incentives that inform them, and this is where the film’s weakness lies. Everyone processes fear differently, sure enough, but this does not forgive unbelievable disregard for their own safety across the board. Despite an awareness of and fear of the zombies in the vicinity, Hye-sun repeatedly cries and shouts at the top of her lungs, and a fellow survivor joins her in a loud wailing session. Ki-woong and a fellow survivor tiptoe through hallways only to swing doors open with utter abandon, despite having no idea what’s on the other side. The lack of noise discipline among the group of supposedly street-smart survivors makes for a difficult suspension of disbelief and keeps the characters from being as empathetic as the passengers aboard the train to Busan.

Seoul Station trades fast-paced action for compelling but imperfect simplicity of character, and social critique as a focal point. The movie does not carry the rugged optimism that its successor film ends with and instead opts to wag a finger at Western society’s callousness toward its most vulnerable members. However, as with most deep horror films, the social diagnosis is the first part of humanity’s treatment plan.

Seoul Station is available to rent now.