The Selfish Gene

Suddenly, Ji Hoon is back to looking like Ji Eun, relieving Yoon Jae. At the same time, Kang Min Joo, a junior of Yoon Jae's, comes back to Korea from her studies abroad and invites Yoon Jae to a welcome-back party, irking Ji Eun. While Ji Eun plans to go to the party with her boyfriend to keep an eye on Min Joo, she faces an unexpected crisis.