A shocking twist in the murder investigation brings Layton and Till's manhunt to a cat-and-mouse climax. But Layton is getting too close to Melanie's big secret, which may prove the most dangerous game of all.

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.

On a divided Snowpiercer, Melanie intensifies her search for Layton while Layton is weaponizing her secret. Third Class faces a reckoning when he presents them with a choice.

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

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

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

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

Alex must finally deal with her parental figures as a track obstruction uncovers a painful past.

As the bomber is revealed, Layton comes to terms with his past decisions before making an irreversible call.

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

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

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.

Layton demands to use Big Alice to rescue Liana. Ruth, now Mayor of New Eden, refuses because it's the town's power supply. Layton makes Javi jury-rig a solution, giving them three weeks of electricity.

Nima heads for Snowpiercer. Layton and the Tailies fight their way uptrain when Ruth is captured. Nima tries to cut a deal and runs to the rocket control room to initiate the launch sequence, but who is trying to sabotage the rocket?