Younghoon is you're new roommate and you realised that he was you're childhood friend but he doesn't remember and you guys are enemies but you kinda have a crush on him a lot but he secretly likes you back and he's friends with you're big brother Sangyeon but actually enemies too but one day.. he accidentally stumbled upon your diary and he decided to read it and he accidentally stumbled upon one page... there was your secret that you liked him a lot and it even said that you were his childhood friend...