Mashiro Haruno, who is 20 years old, woke up in the naked with a guy besides. She did not remember clearly what happened but met by chance this guy at a bar last night, then this morning... She felt embarrassed and rushed to her workplace while the guy wrote his phone number on her hand. Today is her first day in the internship at a design company named ING. Coincidentally, when she met Art Director of the company, she found out that one night stand was her boss. What will happen from now on?