A young girl escapes from a mysterious laboratory and passes out in a rural area. She is discovered by an elderly couple who decide to adopt her and raise her as their own, naming her Ja-yoon. Ten years later, Ja-yoon is a bright high school student with no recollection of her early childhood. Struggling with financial difficulties at home, Ja-yoon decides to participate in a national singing competition, hoping to win the prize money to help her family.

Shortly after her performance on television, strange people start appearing in Ja-yoon's life, including Dr. Baek and Mr. Choi, who exhibit a menacing interest in her. As these individuals close in, they trigger memories within Ja-yoon that hint at a dark past and hidden abilities. Confronted with growing threats and increasingly violent confrontations, Ja-yoon is forced to uncover the truth about her origins and the experiments at the laboratory.