Lee Eun Hyuk lived in Green Homes apartments with his 16-year-old sister, Lee Eun-Yu, and served as the head of their household after their parents' death. A medical student, Eun Hyuk was determined to succeed and secure a better future for them both. Highly competitive and strategic, he often came across as cold and distant. The presence of an academic rival intensified his fear of not meeting his goals, driving him to work even harder to ensure their survival and success.