Ever since her first love made fun of her singing voice, Dahyun didn't just stopped singing. She also stopped talking. She began locking herself from the outside world, never utter a single word but instead writes whatever she wants to say on a piece of paper. 
  
  Because of this, her father and twin brother Kim Youngjae, became fully concerned for her future. They realized that Dahyun can't stay like this forever. So, even if it's hard for them to force her to go out and stop her from homeschooling, they did their best to do those things for the sake of Dahyun's future. 
  
  As Dahyun enters the school premises, lots of things began to happen. There she met two of the school kingkas: The White Prince aka Cha Eunwoo and the Black Prince aka Kim Yugyeom. 
  
  Will Dahyun survive finishing the semester? Or will she return back to her dungeon and forever will be the Mute Girl?