Melanie fights for survival in treacherous conditions, vying to do what others before her could not.

As the train approaches Melanie's retrieval point, Layton leads a furious attempt to try and pick her up but not without some sacrifices.

Mr. Wilford arrives and threatens Snowpiercer, so Melanie makes a move that can't be undone.

An engineering catastrophe on Snowpiercer forces Layton to make a difficult choice, one that might cost him everything.

It all comes to a head as old adversaries clash, with New Eden hanging in the balance.

Wilford presses forward on his endgame while those who are close with Layton grow anxious to learn their fates; Josie tests her newfound ability.

Melanie embarks on her most dangerous mission yet, while Layton reckons with his personal choices.

An exchange is made between the two trains, but a far greater revelation might be just over the horizon.

It's a game of cat and mouse as both Layton and Wilford vie for the upper hand.

Reunited with old friends, the train throws a party. Alliances are tested as the truth is finally revealed.

Layton and Miss Audrey make a risky play for Big Alice, but Wilford has his own plans.

Layton and Till investigate the murders. Wilford leads Miss Audrey down a dark path.

Layton hears the deal: Liana for Big Alice. He agrees and the trains dock at the silo. While Layton, Ben, Till, Ruth, and Alex stew in a holding room, Josie is taken to Headwood. Milius introduces his partner in crime: Wilford.

Layton learns who was responsible for the experiments on Josie and Liana, before also finding out who froze the world.

As the Big Alice crew are granted shore leave on Snowpiercer, Layton and Wilford have differing opinions on the future.

Milius and his Animal Squad storm the train. Melanie realizes something is wrong and shuts the vault doors to the engine. But when Ben's life is threatened, Melanie surrenders the engine.

The rebel forces are on their heels when a dangerous foe joins them. A plan is hatched to take the train, but it may destroy them all.

Layton goes on the hunt, as Wilford works to boost morale. The resistance discovers a threat that could undermine everything they've worked for.

The Snowpiercer crew marvel as a rocket shoots through the sky, crashing nearby. Melanie sends Till and Ben to investigate. Flash forward to nine months later, New Eden blooms.

Alex sabotages the track switch computer and, with Layton's help, escapes to town hall. Till gets the drop on Ace and uses his sniper rifle to save Layton and Alex from Rat. Melanie reveals the identity of Alex's biological father.

Revolution has finally come. As Layton leads the lower classes forward in armed rebellion, Melanie's house of cards collapses.

Tensions between Third Class and First Class are boiling as Melanie stages the trial of the Snowpiercer killer. Third Class threatens a work stoppage, demanding representation on the jury, and Melanie makes a fateful decision about which side to favor.

While Wilford emphasizes his rule aboard his icy train, Layton's pirate train continues its dangerous quest for warm spots, and comes across something entirely unexpected.

Big Alice catches up to Snowpiercer. Milius radios them, inviting Layton over. Sensing a trap, Layton and Josie sneak onto Snowpiercer. Nima is worried Layton will be gassed and attempts to disarm the Greenhouse Car.

Nima needs more samples for his experiments, so Milius sends Wilford and the soldiers to collect. Privately, Milius tells Wolf to kill Wilford. Layton wakes up on an abandoned floor and is approached by humans with toxic gas scars.