Choi Soo-A (Kim Ha-Neul) works as an assistant purser at an airline. She has been working there for 12 years. Her husband is a pilot and they have a 12-years-old daughter. Choi Soo-A thinks she is content with her life, but she meets Seo Do-Woo (Lee Sang-Yoon). Her life changes. Seo Do-Woo works as a part-time instructor in architecture. He has a bright and warm heart. He is married and they have a daughter, but a shocking incident occurs. Due to this, he becomes confused and Choi Soo-A comes into his life.