Haeseong and Jiwoon, childhood friends, spend much of their time together through swimming. One day, Haeseong accidentally catches a glimpse of the unusually impressive size of a certain part of his male best friend, Jiwoon, and begins to feel confused about his emotions. What he once believed was nothing more than friendship gradually starts to change, and Haeseong becomes so entangled in these unfamiliar feelings that he even ends his romantic relationship. Amid crossed expectations and misunderstandings, the bond between the two grows increasingly complicated, leaving them wavering on the delicate line between friendship and love.
