Gong Woo-Jin is a 30-year-old single man and he works as a set designer. Due to a trauma he experienced 13 years ago, he does not want to have a relationship with others. When Woo Seo-Ri was 17, she fell into a coma. 13 years later, she wakes up from her coma. Her mental age is still that of a 17-year-old, but she is now 30-years-old. Gong Woo-Jin and Woo Seo-Ri get involved with each other and fall in love.

Kim Gwan-Chul used to work as an accountant, but now he works as a chief for a company. He is man who follows his principles and uses common sense. He also stands up for those in weaker positions.