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.

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.