Summary (I left myself a memo, so I wouldn't forget LOL):
If I understand correctly, Zeo (ML/seme) was adopted into a rich family and the grandfather wants to use Zeo to marry into another group in order to take over their special magazine that sells gossip (aka blackmail) and insider intel (written by someone named Editor K). He probably had a hunch that Jiwon (MC's trouble-making brother) might be Editor K --- and tries win over Rawon (MC/uke) so he has leverage over Jiwon. Unexpectedly, both Rawon and Zeo are genuinely attracted to each other.
Atm, Zeo and the lady he's supposed to marry are pursuing a fake engagement to get control/screw over over both their families. It's not known yet whether they plan to marry for real as she also has a lover.
Jiwon is currently on a plea bargain with Zeo; Rawon is probably aware that the marriage is a ruse since the lady's lover is the bodyguard; but he still doesn't know that Jiwon is editor K and is in a dangerous position. Jiwon hates the idea that Zeo is pursuing Rawon, as Rawon is his only weakness and vice versa.
dang i forgot the entire plot