I don’t know what you mean by minor spoilers but, if you look at the cover art it will show that heejae is the ML in this story, he does not adopt Garam but he does mentor him bc he sees major potential in Garam’s piano skills. And yes their age gap is large but Garam is an adult and met Heejae as an adult.
For youngjo and naeun I don’t think it should be spoiled it’s a pretty interesting part of the earlier plot in this manhwa! Let me know if you wanna know anything else

I'm on chap 33 and lowkey concerned about youngjo - like why bro what do you gain from making garam feel inferior? And why is the prof kim heejae so special? I mean i do get it to an extent but i wanna know of he's goig be this constant of a presence throughout the story. And what of naeun?
i just read the latest comments here -
FUCK these comments are scaring me - wdym heejae is caring and domestic wtf? With whom? Garam? Isn't their age gap something like 20 years? They're in a relationship now? Or heejae adopted garam??! Idk neither makes sense to me rn. Chat I'm starting to get seriously invested and theres 130 more chapters to catch up - SOMEONE PLS TELL ME WHAT'S GON HAPPEN i don't wanna crash out later. MINOR / BROAD SPOILERS ARE ABSOLUTELY FINE pls just tell me