This drama is a love story between an 19-year-old man and 31-year-old woman, born in the same year and were childhood friends.

Although born in the same year, two childhood friends end up being 12 years apart because they have aged at different places (worlds) for some strange reason. Now Jung Jung Won (Lee Yun Hee) is a 31-year-old woman but Sung Hae Sung (Yeo Jin Goo) is still a 19-year-old boy. Meanwhile, Cha Min Joon (Ahn Jae Hyun) is a chef also interested in Jung Jung Won.