SinB was a longest trainee at Source Music and will be debut in a group named GFRIEND.Everything was went well until a trainee that was only trained for short time and will be debut in the same group as her came to her life.Since then,SinB become cold person to everyone and never talk with the new trainee until one incident happen that change SinB behavior toward that new girl.          

Senior year is ending. The seniors are participating in a scavenger hunt that will be organized by the school alumni at Cheongdamdong High.