The inhabitants of the Tail section plot their next rebellion. Hospitality head Melanie recruits Tailie leader Layton to assist in an investigation.
Several Tailies are punished for the attempted rebellion. Layton and Brakeman Till examine details of the first crime. A devastating accident occurs.
Layton pushes to speak to Nikki and digs into Sean’s past. Melanie and Roche learn of Kronole. A distraction is planned to ease passengers’ anxiety.
After another crime, the hunt for the suspect steps up. Layton and Melanie head uptrain to conduct interviews. The Tailies seek news on Layton.
A trial held for a suspect in the killings leads to a surprising revelation. Till celebrates a milestone. Josie sneaks away to search for Layton.
As Third Class plans to protest the verdict and Layton struggles to recover, Melanie must deal with an unprecedented emergency on the train.
Worried a dark secret about the train will get out, Melanie searches for Layton. Josie tries to see Miles, and Ruth has an unexpected rendezvous.
While First Class confronts Melanie about who’s running the train, Layton and his conspirators mount their biggest attempt to march to the Engine.
Commander Grey, Ruth and the Folgers plan an offensive strike against the rebels. Layton learns a shocking truth. Melanie, in custody, awaits her fate.
Turmoil erupts aboard the train as a leadership change takes hold. A surprise appearance brings hope to some of the passengers, but fear to others.
With Big Alice controlling Snowpiercer's fate, Layton plans to fight back. On Big Alice, Melanie confronts Mr. Wilford and reunites with her daughter.
Layton and Wilford meet in light of Melanie's scientific discovery. Till investigates an attack on a Tailie. Zarah makes a shocking find in the clinic.
Big Alice must help Snowpiercer navigate a treacherous new route. Melanie prepares for a dangerous mission off-train that could change everyone’s fate.
Snowpiercer hosts Wilford for a fancy evening out as they await contact with Melanie. Wilford's visit puts Audrey on edge. Josie boards Big Alice.
Wilford invites Audrey to be his guest on Big Alice while plotting his next move. Layton faces a harsh dilemma. Josie tries to pass intel to Snowpiercer.
Mel arrives at the research station and makes some startling discoveries while struggling to survive and thinking back to the days before the Freeze.
Till zeroes in on those responsible for the latest carnage. Wilford tests Audrey's loyalty. Ruth experiences an epiphany as Layton comes under fire.
As Layton loses more and more support from Snowpiercer's denizens, an engine emergency forces him to call upon the one person he trusts the least.
Wilford assumes control of Snowpiercer, while those who are close with Layton grow anxious to learn their fates. Josie tests her newfound ability.
As the train approaches Melanie's retrieval point, Layton leads a furious attempt to try and pick her up — but not without some sacrifices.
Ben sets out from Snowpiercer on the latest mission to gather ice samples. On Big Alice, Kevin seeks to uncover who is behind the resistance movement.
Snowpiercer welcomes a new survivor as Layton tries to make sense of his visions. On Big Alice, Ruth and the resistance plot sabotage during a ceremony.
Layton and Wilford play a game of cat-and-mouse as the two trains try to outmaneuver each other. Layton asks a favor of Asha, the survivor he found.
Alex, Asha, Roche and Javi each try to deal with personal traumas from the past as Layton and the engineers work to get past a blockage on the track.
As Zarah goes into labor, Layton and Till investigate a fire. Alex visits with Wilford, who remains in suspension. Ben asks Sykes to help Javi recover.
The search for the person who tried to kill Layton culminates in a deadly confrontation. Roche continues to struggle with his anger toward Wilford.
Layton dreams of a fantastical alternate reality after he falls ill. Wilford's sudden recollection sparks a wild theory.
The train takes a detour on the chance that Melanie could still be alive, but a looming threat soon appears in the distance.
A surprise development threatens to derail Layton's plan to reach New Eden. Oz suspects LJ is involved in some dirty dealing when she freezes him out.
Determined to take Snowpiercer to New Eden, Layton threatens war to gain control of the engine, a move that forces Melanie to forge a new alliance.