It is a one shot/sidestory - this girl really wants a boyfriend. So, she runs into a karate club guy practicing from the high school of guys that she wants to date someone popular. He refuses unless she proves herself. So, she bugs him everyday. There was an incident when she fell in the river/water and got drenched. Guy decides to give her his shirt and embarrassed they walk to his house so they can change. His sister was at home and she explains that the guy trains to be strong to protect her and their mom as the father is gone. So, eventually, the guy sets her up with one of his classmates. But, while at a restaurant, she starts to cry and the guy comes in and announces that he likes her - as it was mutual.

It is Citrus Sweat. It is one of my favourites.

that's it!!!