Okay, I'm not exactly sure what people are confused about, but if you ask me I'll try to make sense of it. Here is the summary of what I understood so far:
1 Yuta was a newly arrived prostitute at the Golden Pavilion.
2 Seunghyun gets promoted to second-in-command, which means there’s supposed to be a ceremony where he sleeps with one of the Golden Pavilion prostitutes in front of the higher-ups.
3 Ceremony gets canceled because Jae-il hyung has an emergency surgery, so Yuta is assigned to Seunghyun privately instead.
4 That night actually goes way better than expected. They click.
But Yuta is too proud to admit it because, to him, Seunghyun is just another terrible person like the other gangsters.
5 After that, there’s a clear shift. They start getting closer.
There’s even that scene where Seunghyun tells Yuta he can call him anytime he needs.
6 We still haven’t been shown how this closeness fully develops, but it clearly does.
7 They slowly fall for each other.
Seunghyun promises he’ll get Yuta out of the Pavilion and make him one of his subordinates.
8 And yeah… I’m pretty sure this is when Yuta falls in love.
9 Something important happens off-screen.
What’s implied is that Seunghyun breaks that promise and basically abandons Yuta as a prostitute.
This is what makes Yuta spiral. He becomes obsessed with revenge and spends the next TEN YEARS investigating every single detail of Seunghyun’s life.
11 Now he’s finally putting his revenge plan into motion…
but his old feelings for Seunghyun seem to be resurfacing and messing everything up.
12 Or maybe he’s just pretending. Hard to say
13 Meanwhile, Seunghyun is clearly falling for Yuta too, but he’s conflicted.
14 So he keeps trying to hurt Yuta to push him away…
but he can never fully commit to it because the guilt eats him alive.

Just finished reading and I'm honestly shocked by how many people are complaining. I really don't get why everyone's so confused with the plot or the storyline ??? this is PEAK and I dare say it's even better than Pearl Boy. Their personalities and emotions are so complex, and there's still so much left to unfold in the story. I'm genuinely excited to see where this goes!