Taking place in the 1900s, Yena, a bakery owner meets Yuri, a runaway daughter. Sakura, a normal Japanese girl, signs up for dance lessons with the 'former best dancer of the 4th gen' girl, Lee Chaeyeon. Chaewon, daughter of a Job-assigner, gets a urgent job from her mom to guard the CEO of the world's largest furniture company's daughter, Minjoo. Wonyoung, 'the angel child', friends with Yujin, the troublemaker, finds out that life isn't as easy as they had thought, when they enter highschool. Hyewon, just the average player, wants to fill her heart with emotions, yet she struggles to fill in her empty, longing, heart. Eunbi, a private tutor, lives her life alone, until she finds that things are shady, and discovers the truth about her life. Nako, an anti-romantic, an 'outcast' as they called her, doesn't know what's wrong with her, until she finds someone similar to her, like an angel from the heavens, Hitomi.
All stories connected. 12 hearts in 1.