Since her mother’s death, Jeong Yoojin lived with her mother’s friend in Japan. The ahjussi she lived with tried to cover up the truth about her mother so that she doesn’t have to feel the rejection that her mother felt until she decided to end up her life.

Jeong Yunho knew Yoojin’s mother when he was in his senior year of highschool. Yoojin’s mother was a cleaning service in his school. She was six years older than him and already have 6 years old daughter. He was close to Yoojin’s mother and knew that she had Yoojin when she was in highschool. She was expelled from highschool and kicked out from home because Yoojin’s father was married man.

Yunho decided to go to study in Japan after graduated and take Yoojin along with him. He raised her without his busy parents’s knowing. He finally told his parents about Yoojin when he found a Korean little boy named Changmin when Yunho and Yoojin went to a zooand decided to take care of him.

Yunho’s parents was disagree with his decision at first, they finally agreed on his decision when they realized that Yunho also the son that they adopted. Nine years later, Yunho, Yoojin and Changmin back to Korea, but they don’t know that their decision will lead them to a complicated life.