"Go Eun-hyuk has definitely changed.
Because the eyes looking at me were no longer cold.
Then, was it Go Eun-hyuk who just raised my heart?

Eunhyuk refuses Soo-ae's offer to flirt with him because he thinks about his father having an affair with his music teacher, but he eventually decides to accept her offer as he feels his feelings for her changing.
Despite their promise not to be truly excited about each other, Eunhyuk finds himself becoming more and more attracted to Soo-ae as he carries out the operation.
As Dohwa becomes close with Soo-ae, whom he meets by chance repeatedly, he begins to see Soo-ae treating him differently than others.
Meanwhile, Soo-ae, who is unable to raise her self-esteem, receives a steady stream of text messages urging her to do so, and the content of the text becomes increasingly more threatening...