I haven't read the book or seen a full synopsis of the musical yet but I *think* the gist is (spoilers obviously): Minwoo and Dahye are in love originally but things happen and Minwoo goes to jail, he tries to go back to Dahye when he's out but she refuses him (because she resents him for what he did and she'd started seeing Hyuntae in the meantime). I'm not sure where Jenny fits into the chronology, I think she meets Minwoo before he goes to jail, when he's in a bad place - she works at the hostess bar Minwoo's aunt owns and falls for him but he's still in love with Dahye. I'm fairly sure he sleeps with her mistaking her for Dahye (probably while he's drunk and/or high), which results in a baby it's A Lot not that important but also Hyuntae isn't Minwoo's biological brother, he's a sunbae at the school

@@ChangsubSubs THANK YOU! Oh, so Minwoo and Hyuntae are not real brothers, that is why the family name is different. Before I got your explanation, I wondered why the brothers had different family names, I thought maybe they had the same mother but a different father. Hm, knowing the story more I feel like Minwoo is a red-flag guy 😅