이 죽일놈의 사랑

A Love To Kill:

Kang Min Joo (Kim Young Jae) was more than a brother to his younger brother Kang Bok Gu (Rain). He is both a mother & father to Bok Gu. They came from a dysfunctional family where his father was invovled in gangster crimes and thus their mother left them.
10 years ago, Kang Min Joo ran away & Bok Gu now lives his life stealing and threatening people to give him money with his girlfriend (he eventually stops because he is too "kind hearted"). Bok Gu finally reunites with his brother Min Joo after 10 years. The joy is cut short as Min Joo steps off the guardrail of his house while reaching toward the face of Cha Eun Suk (Shin Min Ah) on an electronic billboard with the announcement of her engagement to a rich heir. He becomes a human vegetable as a result of the suicidal fall and Bok Gu wants vegeance when he realizes that Eun Suk and his brother were lovers prior to her becoming a top movie star.
His plan is to make Eun Suk suffer the same agony that his brother did. To be closer to Eun Suk, Bok Gu changes his job from a K-1 fighter to her body guard and plots his revenge. His plot is to make her fall in love with him and suffer the same loss that he did by repeating the tenderness and special memories that his brother Min Joo and Eun Suk shared. As time goes by, Bok Gu was drawn to Eun-Suk and he is agonized by the struggle between love and his duty for revenge.
Why must this be a sad ending with Bok Gu & Eun Suk frozen to death in the snow? WHY???