Jennifer Connelly stars in "Snowpiercer"

It can be hard to imagine a completely frozen-over Earth in the middle of a sweltering July, but that is the catapult of the story behind the new sci-fi series, "Snowpiercer." A new episode airs Sunday, July 12, on TNT.

The last surviving humans on the planet all boarded the 1,001-car-long, super-speed train, Snowpiercer, before the Earth became inhospitably cold after an ill-advised attempt to cool the effects of global warming went horribly wrong. At the final boarding call for passengers, people without tickets rushed the train, violence broke out between those desperate for survival and the guards of the Snowpiercer, and a handful of those desperate souls staked their claim on the final carriage of the train, becoming Snowpiercer's "Tailies."

Subjected to abhorrent treatment under a strictly enforced class system, the Tailies are given the bare minimum necessary to survive. They are fed disgusting, constantly shrinking rations and treated as less than human by those who enforce the status quo. Tailies with special skills are selectively chosen as needed to ascend through the train for whatever jobs need doing for the upper classes, and those that are returned to their home car bring with them intel about the rest of the train.

Seven years into the train's never-ending journey, Tailies have banded together to organize a revolution to force their oppressors to improve their living conditions. Andre Layton, portrayed by Daveed Diggs ("Black-ish"), is the leader of this revolution, and when he is unexpectedly plucked out of the last car to investigate murders in the upper classes, the Tailies enact his planned takeover without him.

As a former homicide detective, Layton investigates a series of murders that the First Class was wholly unprepared to handle. Layton is surveilled at a distance by the mysterious head of Hospitality, Melanie Cavill (Jennifer Connelly, "Labyrinth," 1986), and more directly by Brakeman Till (Mickey Sumner, "Low Winter Sun"), a security enforcement officer who is saved from the bloody uprising by Layton.

After watching him leave them, other Tailies involved with the revolution splinter over whether they believe Layton will return to their car after his work in the upper classes, or if he will remain there, having had a taste of a better life and forgetting the bigger goal of creating equality among all classes of passengers aboard the Snowpiercer. Without much knowledge of the 1,000 cars beyond the one they call home, the Tailies are forced to push forward in the hopes of gaining ground in an essential carriage and holding resources hostage as a bargaining tactic.

The Tailies aren't the only characters in "Snowpiercer" secretly constructing a strategy for change. Cavill is calm and stern whether she's dealing with the concerns of First Class passengers or explaining to Layton the intricate balance that must be maintained in order to grow a perfect strawberry onboard the Snowpiercer, obviously suggesting he read between the lines and recognize his place as a member of the lowest class of passengers. It is clear that Cavill has more up her sleeve than she is letting on while she has her Hospitality jacket on; when she returns to her quarters at the end of her day to literally and figuratively let her hair down, she is greeted by a poster of chess strategies.

Jennifer Connelly, Mike O'Malley and Daveed Diggs in "Snowpiercer"

If "Snowpiercer" sounds familiar to you, that may be because the series is a reboot of the 2013 film of the same name that starred Chris Evans during a rare break from portraying superhero Captain America in the Marvel Cinematic Universe series of films. The movie takes place 17 years into the train's run and references past Tailie uprisings that may be the ones we see unfold in the series.

That film was itself an adaptation of the 1982 graphic novel "Le Transperceneige," by Jacques Lob and Jean-Marc Rochette. The film's director and screenplay writer, Bong Joon-ho, also wrote the screenplay for the 10-episode "Snowpiercer." Bong received three Academy Awards for his 2019 film "Parasite": Best Film, Best Director and Best Original Screenplay. That film, like "Snowpiercer," is a sharp examination of the classist structure of society and the violence and deception it often takes to ascend beyond the class you happen to be born into. In "Parasite," being poor is a stink that you just can't wash off, and in "Snowpiercer," you'll always be sent back to where you came from when the upper classes have gotten what they want from you.

All aboard the Snowpiercer! Class warfare is erupting, and you're either part of the revolution or you're the one facing it from your First Class train. Do not miss the penultimate episode of "Snowpiercer," airing Sunday, July 12, on TNT.