Kim Taeyeon is your typical type of deliquent that goes around picking a fight with their neighbouring school and this had cause a great damage to SM High's reputation.The principal had been thinking of expelling her for a lot of times already but because of his niece;Tiffany Hwang who had a sister-like relationship with Taeyeon convinced him not to do so,he didn't,in one condition.

Taeyeon must be under her care for the rest of her high school years.Hearing this,Tiffany agreed to it almost immediately just to save Taeyeon from getting expelled but little did she know,she was about to fall hard for the younger girl during those period of time.