Alex tells Melanie her snow sample is just water and dirt. Melanie tells her it was snowing which Alex says is impossible.
Till picks up Layton and reports an assault on a Tailie woman overnight. He and Roche make her Train Detective and set her on the case. She finds out the victim was Lights and that her fingers had been cut off.
Layton and Roche use food to get Kevin to tell them how many people are on Big Alice and how Icy Bob can withstand the cold.
A communique comes from Wilford, offering to exchange Melanie for Kevin.
Kevin reports to Wilford in his private car where Wilford offers him a hot bath. Wilford climbs in with him and gives him a razor blade to commit suicide for betraying Wilford.
Zarah discovers the Jane Doe recovering in the clinic is Josie. She poisons the IV to kill her but changes her mind at the last minute. She goes to Audrey for advice and Audrey tells her she must protect Layton at all costs.
Melanie, Javi, and Ben discuss the idea that the CW-7 is falling out of the atmosphere. They launch a weather balloon and it reports back that the atmosphere is warming.
Layton sends an invitation to Wilford to meet about a scientific discovery and he accepts, planning to have Alex kill Layton.
Pike sells his weed to Terence. Osweiller and LJ come to Terence for a job.
Wilford is welcomed to Snowpiercer and initially disputes Melanie's finding. Her plan involves a research station and he demands that she be the scientist left behind. She agrees. Wilford calls off Alex from killing Layton.
Till realizes that Lights' injury turned her hand into a Wilford symbol.
Zarah tells Layton about Josie.