Throughout the film, Se-ri attempts to get close to transfer student Han Yun-seok solely to secure a free 'Seoul Magic Straightening' treatment from his mother's salon so she can confess to Kim Hyun. However, as Se-ri assists the injured Yun-seok, the two share quiet moments, reading comic books and bonding over tangerines.
During a school field trip, when the moment finally arrives for Se-ri to confess to Kim Hyun, she realizes her heart belongs to Yun-seok. She admits to Kim Hyun that while she used to like him, she has fallen for the person who accepts her just as she is.
The Conflict: Yun-seok’s father, a strict medical professor in Seoul, abused Yun-seok and his mother, causing Yun-seok to give up on his university entrance exams and flee to Busan. When his mother is hospitalized in Seoul after another confrontation with the father, Se-ri travels to Seoul to check on them. Overhearing that Yun-seok might move to the U.S. for a fresh start, Se-ri selflessly decides to step back. She lies to Yun-seok, telling him she only saw him as a friend and cuts off contact so he won't hesitate to leave.
Ending: Years later, Se-ri is a university student who now proudly wears her natural curly hair. While visiting a coastal cafe in Busan (run by Gong Yoo and Jung Yu-mi's characters), she encounters Yun-seok, who has returned. Having resolved his past, Yun-seok reaffirms his love for her. The film concludes with the two sitting together happily, proving that true love untangles all misunderstandings.