The story of Kim Yu Mi, who became a star writer after much effort. Although she achieved great success as a romance novelist who steals the hearts of readers, love remains the most difficult challenge for Yu Mi. The village of her cells seems to be in a state of quiet pause with nothing exciting happening until the arrival of Sin Sun Rok, who brings a refreshing change to Yumi's life. 

Yoo Mi is an ordinary single working woman. She is not good at expressing her feelings. Through her romantic relationship and work, she grows as a person and finds happiness in her daily life. Yoo Mi has cells in her brain that represent different emotions like love, violence, rationality, good, and bad. These tiny cells in her brain work actively for her. They deal with her emotions and troubles.