Feeling lonely after a breakup with her boyfriend, Iseo suddenly finds herself feeling a strange sexual attraction toward Kwon Itae, her father's longtime friend. Then, late one night when Itae stays over at her house, Iseo completely falls for his subtle seduction. The man she always thought was kind and gentle finally begins to reveal his hidden feelings... The secret, true nature of the father's friend she thought was a gentleman. And Iseo, who starts seeing her father's friend as a man. A forbidden relationship that should never have begun takes an irreversible turn.