Jessica Jung is a certified good girl. Her parents died when she was sixteen years old and so, making her boyfriend, Kim Jaejoong, stay with her. Meaning, they live together. Besides that, everything has become beyond perfect.

One day, Jaejoong was said to leave the country because of his sick grandmother abroad. Leaving Jessica under his best friend, Lee Donghae's care. Jessica is aware of Jaejoong's friends to be like him — kind, handsome, gentle; a gentleman who treats girls with respect. Even if she doesn't talk to his friends, she thinks they are the same with him. So what will happen if Donghae were to stay in Jessica's house? Is he the guy Jessica thinks he is?