Middle-aged man Gi Jun and a college drop-out In Ae meet on a plane to Busan. Their relationship grows stronger, and they finally become lovers. When Ji Suk, Gi Jun's wife finds out about their relationship, she also tries to have an affair with another man. In Ae decides to leave Gi Jun and her love for him behind as a beautiful memory. The marriage of Gi Jun and Ji Suk is saved at the brink of destruction.