Marketer Oh Ha Na and flight attendant Choi Won are old friends who have built a strong 17-year-long relationship together. They've always depended on each other and have remained close through the years. Could the fact that they've so comfortable with each other be the reason they are unable to realize when feelings other than friendship begin to develop? Choi Won, a vice manager flight attendant, gains a female friend in a new coworker, and Ha Na doesn't realize how much she is bothered by it. However, Ha Na, reuniting with her former love, pianist Cha Seo Hoo, ignores Won's feelings.