Compassion.

Choi Seok, a historian, raises Jeong-im after her parents pass away. But when her gratitude turns into feelings for him, he is criticized and so leaves the school. When Jeong-im is hospitalized, he gives her a lump sum of money and leaves for Hokkaido, Japan. When Jeong-im finds out the truth, she and Oh Jin-wu, an admirer of hers, go to Choi Seok who's now fighting brain tumor...