Jinju is first seen, swimming around and collecting coral in the Aquarium car where she works as a chef. Melanie visits her and asked if she could help Nikki Genêt recover, working with Klimpt.
Jinju is in a romantic relationship with Bess Till,[2] which Till prefers to keep secret for the time being. Jinju believes Till to be uncomfortable with her comparatively lower social status since Till is a Third Class citizen while Jinju is a Second Class citizen.[1] She then makes Bess Till a second class. They break up after the rebellion due to their differing views on it.
Melanie shares the most important secret to her, that how she's the one actually running Snowpiercer under Mr. Wilford's mask. The two of them shares important discussions such as what to do at LJ's trial or when the Third Class is putting up a strike. Jinju would try several times to get Melanie to meditates and help her feel better.
Jinju: "I thought the boss could use some comfort food tonight. I bet you can use a drink."
Melanie: "What should we toast to? How about whatever is making you smile so much right now? Or is it whomever?"
Jinju: "Is it that obvious?"
Melanie: "Oh you’re beaming. But there’s something I have to tell you. I’m bringing Nikki Genet out of the drawers. We locked up the wrong person. I have no choice. How bad will she be?"
Junju: "Two years in there. Won’t be pretty."
Melanie: "Will you monitor her? Work with Klimpt? Learn what you can."
Jinju: "And if the people start asking the wrong question?"
Melanie: "I’ll handle that. Then, once this murder’s solved. The other work can continue."
Jinju: "We can’t ration any more power to Ag-Sec unless we start canceling crops."
Melanie: "We’re not breaking rotation."
Bennett: "Water won’t flow for a couple days at least. Not until the crack in the hull is seal."
Jinju: "Then we only have what’s in the reservoir for Third, Ag-Sec and Tail."
Melanie: [ sighs] We ration the people, not the crops. Third and Second will get 15 minutes of running water a day, and the Tail will have to survive on what they’ve hoarded."
Bennett: "Is this what the start of a resource crash feels like? Starving the train from the tail up."
Jinju: "It’s not just the beef. It’s manure for fertilizer. It’s bovine cultures. We use their methane."
Melanie: "I know. It’s bad. But how bad stays between us. In the meantime, we press ahead with selecting the new apprentice and we bolster faith in Wilford to get them through."
― Jinju discuss water lacking problem with Melanie and Bennett, and revealing she knows about how Melanie is pretending to be Mr. Wilford.
The whole time, Erik’s focus was Lilah Junior. I was as much her hostage as I was his. That was what they wanted, Erik and LJ, to kill us all in a nihilistic rage. But the Eternal Engine is still here.
Bess: "Look, I can't explain. I just need you to stay out of Third today, okay?"
Jinju: "Why? What did you do, Bess? Is this about Layton?"
Bess: "Just stay home. Please."
Jinju: "I asked you point blank whether you were helping him, and you lied to my face?"
Bess: "Jinju... Why did you ask me to steer clear of Melanie Cavill?"
Jinju: "Because you're messing with things that you don't understand."
Bess: "What things? You knew she put Layton in a drawer, didn't you? You're protecting her."
Jinju: "I was protecting you, Bess. You. Bess: "Did you know... she tortured a Tailie to death. (silence) I wonder, Jinju, just how many deep, dark secrets about this train you really do know." Jinju: "Please don't make me choose between you and the train." Bess: "Just stay in here today."
― Bess to Jinju before the revolution in Jinju's quarter.
Melanie: "Oh, God. I’m shaking. How did you do that?"
Jinju: "Coercion and gifts. How do you think? But we don’t have time. Come on, Mel. We have to go. Mel. There are still reasonable people uptrain. We can rally support. Take the Folgers head-on."
Melanie: "First is lost."
Jinju: "The entire train is lost. But we have to try."
Jinju: "They raided Poultry, damaged Aquaculture, stole half a car of lettuce. They're taking anything they want. Now I have serious supply-chain issues, and you want the whole train to have equal calories?"
Bess: "That's your first priority."
Jinju: "We're down 16 trained men. We're going on 48 hours no sleep."
Bess: "Oh, thank you for your efforts, Jinju. [...] I just don't understand how you could just keep such a big lie from me. And the whole train."
Jinju: "Because this is the alternative. And if the people needed a Wilford, why deny them that hope? Come on, Till. Would you really rather be alone?"
Bess: "I'm not alone. I've got my sisters and brothers I stood with and a responsibility to Snowpiercer I have never felt before."
Jinju: "So we finally agree. The Train comes first. (kisses) You know what they say when you break up on Snowpiercer."
Bess: "See you around."
― Jinju to Bess after the revolution in a Greenhouse Car.
