There are two girls named Seohyun and Yoona.They are both best friends since kindergarden and they are the dectectives who solve mystery cases.One day,when Seohyun and Yoona's class teacher has decided to transfer them to another better high school named" Donghwa High School".The very next day,they entered the new school and and met a group of freinds named Hara,Luhan and Krystal..Hara noticed that one of the girl is Seohyun.Seohyun has been an enemy of Hara since 5 years ago because of Seohyun's excellent grades..Ringgg..".Is time time for class " said a teacher.Soon,the teacaher arrange their seats in class.Seohyun got to seat with Yoona...Hara was sitting behind them while whispering to her friend Krystal about Yoona and Seohyun...