What happens to a brother and sister who are adopted by different families and then reunited as adults? Seo Gun (Gong Yoo) and Seo Ha Neul (Sung Yuri) become brother and sister legally when Gun’s father marries Ha Neul’s mother when they were kids. But when their parents are killed in an accident, Gun and Ha Neul are sent to an orphanage and then adopted by different families. Ha Neul is adopted by a wealthy family in Korea and given the new name of Park Hae Won to replace a daughter that her new parents lost. Smothered by her new adoptive parents and brother, Park Tae Won (Yoo Ha Joon), Ha Neul escapes everyday to a secret job at an aquarium, working for the curator Kang Dong Ha (Namgoong Min), who begins to develop feelings for her. Gun is adopted by a poor family living in Australia and grows up to become a small-time gangster. When Gun hears from his best friend back in Korea that Ha Neul is living a luxurious life with her new wealthy family, Gun decides to return to Korea to swindle some money out of his sister. But his adoptive sister, Goo Hyo Joo (Lee Yeon Hee), doesn’t want to let Gun out of her sight and follows him to Korea. As Gun reunites with Ha Neul, will he follow through with his moneymaking scheme or will his feelings for her get in the way? “One Fine Day” is a 2006 Korean drama series directed by Shin Hyun Chang.