Mr. Wilford has arrived. And as this new threat rattles Snowpiercer to its core, Melanie makes a move that can't be undone.

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

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

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

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

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

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

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

Wilford presses forward on his endgame, as Layton sinks to new lows.

Hope is a powerful motivator. As things hit their darkest point, Layton hatches a plan.