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.

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.

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.

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