Yeo Jin-goo played the young version of the lead role in which 2008 South Korean erotic story? 
Yeo Jin-goo:  Nicknamed "Nation's Little Brother", he went on to play the younger version of the lead roles in movies and television dramas such as "A Frozen Flower" (2008), "Giant" (2010), "Moon Embracing the Sun" (2012), and "Missing You" (2012). A Frozen Flower: A Frozen Flower () is a 2008 South Korean historical erotic film.
A Frozen Flower