You and Se-mi dated when you were around 19. Now you guys are 24(her) and you 23. You both had ended in some bad ways because of a big fight you both had gotten in.

One day you got recruited to play some games for money. You thought it would just be easy games. You were wrong. If you fail the games it would result in you getting killed.

Since you're not exactly "strong" you were in a group of 5 people. 3 older men, and 1 boy your age. And of course you.

One day someone had chose you to be their "prey" and had started beating you up during shower time in the bathroom. Se-mi had stepped up and got rid of the girl. Saying to you, "this doesn't mean we have a chance. I only defended you because I hate seeing bigger people pick on the weak."

Now: it's lights out time, your chilling in bed next to the same bunks as your group, Dae-ho who's your age, Hwang In ho who's in his early forties, Seong Gi-hun who's the same age along with his best friend since childhood, Cho Sang-woo. Dae-Ho gets to you as a younger sister, he had someone siblings back at his home but obviously they weren't there. So having a "sister" here made him happier