Snowpiercer is a clever, original, violent, highly entertaining sci-fi allegory. Snowpiercer is implausible fantasy, but it commands attention in every frame.

The story is adapted from a graphic novel published in 1982 by two French guys. Director Bong Joon-ho just happened to find the source material in a bookstore in Seoul in 2005. Bong, a Korean making his English language debut, also co-wrote the script.

Here’s the setup: Just a few decades from now, in response environmental wackos screaming about global warming, the world’s nations release something called CW-7 into the atmosphere. It works too well and the result is a frozen planet.

The only survivors crowd onto a train, which moves continuously on a track that goes around the earth. Those who populate the train are a microcosm of the world’s citizens. The elite types up front, those lowest on the socioeconomic scale at back. (The train’s name comes from its ability to burst through avalanches that have covered the rails with snow.)

Curtis (Chris Evans) and sideman Edgar (Jamie Bell) lead a group of downtrodden “back of the train” people toward the front of the train and a confrontation with Wilford (Ed Harris), who has been unseen by the Curtis and company for the 17 years they’ve been on board.

Key players accompanying Curtis on his quest are Tanya (Octavia Spencer), Minsoo (Kang-ho Song) and his daughter Yona (Ah-sung Ko). Tilda Swinton plays semi-comic character Mason, a Wilford operative. The journey to the front is filled with gritty battles and amazing surprises.

Chris Evans, whose improvement as an actor is visible in the latest Captain America movie, does a nice job as Curtis. He balances the physicality of the role with appropriate humanity. Ed Harris is solid as the smart-ass know-it-all Wilford.

Snowpiercer rises above other apocalyptic sci-fi because of its story and the skillful telling of that story by Bong. Lucky for us that he chose to pick up that graphic novel that day.