After Kang Soo's motorcycle accident, Jeong Man is told to prepare for the worst. Jae Hui approaches Jeong Man and offers the chance for Kang Soo to participate in the happiness research. Jeong Man agrees because he believes it's the only way to save Kang Soo. Meanwhile, Kang Soo begins the experiment, but amidst the happiness, he begins to believe that something isn't right. (Source: KOKOWA)