Of course, Jae-in’s knowledge is not on the same level with others, and she protects herself in every way since she’s afraid of being seen through. Hye-ryung (played by Hong Su-a), a big sister in the class, also dislikes Jae-in and finds fault with her in everything. Jae-in has no other choice but to bear it. What made Jae-in happy from the setbacks is that she started to like a fellow student named No-young (played by Gong Yoo). However, Jae-in felt upset when thinking of her real identity and age. The operation finally made progress, the target started to believe Jae-in and she got important clues. However, something changes again....