So blond hair boy can smell people's feelings because he has a really good sense of smell and one day he gets kissed and he remembers that person's scent so he tried looking for them and it turns out to be black hair boy.
Spoiler
Choi kanggo: has a sensible nose, he can smell feelings, so he can smell Kamin liking him and fell in love with him.
Kamin: loves sprout man, saw kanggo disguised as sprout man in the school festival an fell in love with him
Kamin grandma: hates Kamin, blames him and his mom of killing his son (Kamin father)
Kamin mother: left Kamin with his grandma because she didn't have money or time to care for him
Kanggo mother: is the voice actress of the hero companion of sprout man, Kamin idolizes her.
Kanggo sister: care a lot for his sensible brother, she makes doujinshi and fanarts of sprout man, Kamin idolizes her too
Kanggo uncle: is gay and going out his his friend
Green haired friend: kanggo rival
Other friend: Kamin friend, likes sprout man too
Thank youu. Now I remember
LOL, I FORGET THE STORY. PLS SOMEONE REMIND ME.