Min Gi-heon (Gong Yoo) is an ex-agent of the intelligence agency, and Seo Bok (Park Bo-gum) is the first human clone created through stem cell cloning and genetic engineering. He possesses the secret for eternal life. They get entangled in dangerous situations as several forces want to take control of Seo Bok....

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....