Hwang Ahyoung is a classmate who lives next door to Hyunsoo. She left Hyunsoo in her second year of high school and went to the U.S. for studies. Hyunsoo, who is now a college student, one day at home alone sees an underwear shopping mall called ‘Flirting’. Heart pounding, he witnesses an intimate affair between a man and a woman in the house where Ahyoung lived! Hyunsoo is so shocked that he freaks out. 

The next day, Hyunsoo wakes up to see Ahyoung, who he’s dreamt of, as the boss of the underwear shopping mall! What’s more, she wants him to help with the business! In a confusing turn of events, among the staff in the underwear shopping mall, the woman who had an affair the previous day recognizes Hyunsoo. Things begin to take a strange turn…