Song Kang the most popular guy and one of the A3 member in Leejo High school. The A3 consist of Oh Sehun ,Song Kang and Kim Mingyu. Mingyu is a spoiled brat a play boy, Sehun is a fun and kind person and Song Kang is a cold hearted handsome guy. And they are always accompanied by Song Jieun (Song Kangs' sister) . Everything was going well untill a couple of girls transfer into their school. The girls being Kim Jisoo and Kim Jiyeon(Jisoo calls her Bona). Lets see how the lives of these three boys and girls get tangled together . And lets see how the two adults Yoona and Junho help them.