After a longtime gaslighting by a sex partner, Yeon-Su thinks of himself as a masochist. An elementary school swimming instructor, he starts teaching Cha Ju-Hwan, a top star who secretly needs to learn how to swim for filming. To Yeon-Su, who believed life was over and there was nothing to see at 29 years old, his world takes a 180º turn when Cha Ju-Hwan approaches him. "I like to be hit, and my partner likes to make me this way." "Then do it with me too." (Source: Ridibooks)