There's a girl who is hurted, even she is too perfect to be hurted. And there's a friend who always by her side, calming her each time she's hurted.   

You live with your aunt since your parents passed away. You called your aunt as 'omma'. One day, you involved in an accident with your boyfriend, Baekhyun. Since that, you lost all your memories and because of the pain, your have a below average IQ of 65. Your aunt's son, Oh Sehun, always thinks you burden him. And one day, one unexpected day, he fell inlove for you~~~