Chaeyeon and Sakura are dating and the both of them will do anything to keep it a secret. Yena knows about it and will always try to out them, but with sensible Eunbi's help, the couple is safe.

Irene's moving into her new apartment unit after traveling from Daegu because she enrolled in a high school in Seoul. At the moment she brought out her luggage and heavy boxes, a certain girl appears in a suit, pledging to serve her.

Chaeyeon Uchiha is the best kid in the classroom, while Sakura is the weakest. Both of them had a bad impression of each other in the beginning, but after their trainer pairs them up for a D rank mission, they bond fast.