A young couple, Young-joon and So-yeo, have a stable marriage. On the day that their mutual friend opens a wine bar, they come across Min-jae and Yu-na, a couple quite the opposite of themselves. After their conversations at the bar, Young-joon becomes a client of fashion consultant Yu-na, while hotelier Min-jae agrees to help So-yeo with her travel arrangements for her Hong Kong business trip. So-yeo meets Min-jae by chance in Hong Kong, while Young-joon trades suggestive remarks with Yu-na who visits him on a consulting session. That night, the four of them find in the other partner what had been missing in their respective marriages.