Aboard Big Alice, Wilford makes the morning announcement, lauding the sacrifices made by Icy Bob and encouragin his crew to look forward to retaking Snowpiercer.
Melanie wakes up in bed with Ben. She's conflicted about leaving Alex but Ben reminds her there's a bigger picture.
Alex warns Wilford that getting Snowpiercer over the mountain is going to be difficult. She also points out that their fresh food is making the rest of the crew crazy. Wilford thinks it's a good thing and, with Melanie departing the train, he believes that Layton will be vulnerable.
In Snowpiercer's engine car, Layton listens as the engineers describe what they are about to attempt. Melanie sends a list of needed supplies to Big Alice and arranges to have Alex help her when Wilford refuses to let Ben accompany her aboard.
Melanie advises Layton try to keep Ruth on his side.
Roche discovers that Till is sleeping in the brakemen's office, now that she's broken up with Jinju in Second Class.
Layton and Melanie arrive at the border. The hatch opens and Wilford greets them, seated in a throne-like armchair. He tries to negotiate down their list of supplies. Melanie stands firm. Layton adds that Snowpiercer has other needs and is willing to trade fresh food and drink too supplement the diet over on Big Alice.
Wilford escorts Melanie to the supply cars and Alex joins her there. They discuss the variables key to Melanie's survival and what her leaving means to their relationship. Alex gives Melanie a tour of her spaces.
Layton goes to see Josie who has been filled in on everything by the Tailies. Josie holds Layton accountable for the Tailies who died in the revolution and reprimands him for not following through on their promises and jeopardizing his leadership.
Pike and Terence talk business, specifically the fact Pike can't get anything over the border. Terence makes it clear that if Pike doesn't have product for him, he doesn't want him in his loft.
Till has Lights show Layton her mutilated hand. The rumor point to the breachmen as the attackers but Layton warns the Tailies to protect themselves only. Till promises Lights that she'll solve the crime and get justice for her.
Layton sends Roche with Till to question the breachmen.
Boki speaks for the breachmen and makes it clear that their loyalties lie with Wilford. They do deny attacking Lights, though.
Alex takes Melanie to her bunk. They discuss the plan again. Melanie lays a hand on the train and diagnoses a wheel out of alignment.
She lays a hand on Alex's face in a similar manner. Alex welcomes the contact.
Ben and Layton discuss Wilford and agree to keep no secrets from each other.
Wilford checks in on Icy Bob who was exposed to -96 degree temperatures for nearly an hour. Wilford demands more extreme cold exposure.
Alex tries feeling the train and Wilford sees it. Wilford gives her a pep talk about wanting Melanie gone.
When Melanie makes contact about her departure, Wilford informs her that Alex will be driving Big Alice for the final push through Neckbreaker.
In order to get Snowpiercer over the mountain, they'll have to cut power to First and Second Class. Ruth is put in charge of getting everyone in First and Second to muster stations. Layton goes to stay with Josie and finds her trying to remove her facial bandages. He helps her so she can see the damage.
With the train's speed dropping, Wilford proposes they hit the booster on Big Alice before the curve, putting the train at risk of derailing. He thinks it's an excellent teaching moment for Alex.
In the Night Car muster station, Miss Audrey is welcoming people in with an inebriated air which Roche notices. Everyone is secured and Snowpiercer cuts the power but it's not enough.
Alex hesitates on hitting the booster and Wilford taunts her with the idea of spending more time with Melanie. Alex hits the booster and Melanie remains encouraging. They successfully climb the mountain and Alex sheds a tear for the effort.
Till and Roche keep an eye on the breachmen who give them the Wilford salute defiantly. Pastor Logan comes by to see Till and gives her a St. Christopher's medal.
Layton tells Josie about Melanie's departure and, although she still hates Melanie, she recognizes that, between Layton's child and Melanie's mission, that is the new cause for the Tailies.
Layton and Ruth accompany Melanie to her departure. She leaves Layton some warnings and words of wisdom. After she walks away, Layton calls out Pike who is nearby, eavesdropping. Layton directs him to re-establish his smuggling contacts but with Layton pulling the strings.
At the hatch, Melanie tries to advise Ruth and asks her to keep an eye on Alex for her.
Alex helps her prepare for departure. Melanie reminds her that Wilford's evil isn't hers.
Alex clings to her in farewell, admits that she wanted to keep her longer. Melanie tells her that there are trustworthy people on Snowpiercer.
Snowpiercer drops a flare and supplies. Melanie jumps.