Snowpiercer circles a frozen earth keeping Earth's survivors alive, until murder threatens order.

Layton investigates the murder while gathering intel. Melanie faces a resource crisis.

Layton descends into the black market, while Melanie stages a prize fight to defuse class tension.

A twist in the investigation brings Layton face-to-face with the murderer.

Tensions between Third and First Class are boiling as Melanie stages the trial of the killer.

Layton lays track for revolution, while Melanie faces an engineering emergency.

Melanie intensifies her search for Layton, while Layton is weaponising her secret.

As Layton leads the lower classes forward in armed rebellion, Melanie’s house of cards collapses.

A dangerous foe joins and a plan is hatched to take the train, but it may destroy them all.

Layton and Melanie realise that the greatest threat to survival is right over their shoulders.