Six months have passed.

Wilford is chasing Layton's pirate train, about a month behind them. Javi silently drives the train.

Everyone on Snowpiercer is bundled. Dr. Pelton and the teacher, Ms. Gillies, work with a resistance effort to Wilford's rule. Pelton sends a message with Winnie. She runs through the Night Car where Oz plays the piano and LJ tends the bar.

Winnie delivers a message to Pike who passes it on to Ruth that signs of Snowpiercer have been sighted. They don't know if Melanie's aboard the pirate train or not.

Pike questions whether Layton will ever return.

Ben pulls a sled of equipment to a site and reports back to Layton that he'll start pulling ice samples. Josie and Layton monitor the data while Till and Alex comment on the futility of their quest.

Alex alerts Ben on a thermal switch blow-out. He insists the train can handle it.

Till goes to check on Miss Audrey who is locked in a cell in the library. Sykes brings in the ration packs for the three of them and Martin Colvin.

A weather front starts moving in. Ben starts to head back to the train. He notices the ice layer is cracking under his snowshoes and then falls into a cavern, a room with furniture and computers. His signal is lost and he is knocked unconscious.

The four in the library discuss what will happen when the trains reconnect.

Layton calls down and tells Till to lock everyone down and return to the engine.

Layton prepares to rescue Ben. Josie insists on going with him. Till pilots the train out while Alex keeps the engine working. They leave Layton and Josie, planning to return in about a half-hour.

Onboard the main train, Kevin shows Wilford the books, noting things are being stolen. Zarah brings in the engineering reports. Kevin wants to cull passengers, Zarah wants to cull decommissioned cars. Wilford wants neither plan.

The resistance distributes resources throughout the train.

Kevin checks in with Oz and LJ for information on who is in the resistance and who might be the ringleader.

Wilford check on Javi's scars.

Kevin's gang discovers Ruth's hideout. Pike and Ruth move quickly to escape. Pike leads her to a cubby space in the unheated First Class cars set up with a heater where it's only -12 degrees.

Layton and Josie anchor themselves to save Knox.

Audrey and Martin put a mutiny plan into action, and try to force Sykes to join them. She refuses so they lock her up.

Layton talks to keep Ben awake.

On the train, Till tells Alex to talk out the engine issue. Audrey makes her move, knocking Till out. Audrey lights a cigarette in celebration.

Till recovers but can't get up into the engine because Martin's on the trap door.

Josie and Layton start lifting Ben out of the hole. Layton sends Josie to the train with Ben. Layton explores the space and finds signs of life and a generator.

Suddenly, he's attacked by someone else in an enviro suit.

The fight causes him to use up his oxygen. He starts to pass out.

Audrey tries to discourage Alex and convince her to bring the pirate train back to Wilford.

Till gets out through a different route and knocks Martin out. She and Audrey argue over what to do. Audrey tries to drive the train and Till knocks her out.

Layton hallucinates a sun-drenched world. He wakes up.

Josie tries to hail Snowpiercer as well as Layton to no avail.

The train returns. Josie gets Ben onboard. She wants to head back for Layton. They spot him returning, carrying someone on his back.

On the main train, Javi drives the train. LJ and Oz are content in their work. Kevin punishes the resistance members he captured by having other passengers throw buckets of waste at them.

Wilfred dines in the laboratory car where the Dr. Headwood injects Zarah's embryo while Zarah lies unconscious.

Ruth huddles in her cubby.

On the pirate train, Layton watches over his attacker, an unconscious woman. He continues to have flashes of the sun-drenched vision he experienced.