In A Love to Kill, Bi/Rain/Jeong Ji-Hoon plays a tough guy as the role of a K-1 Fighter, Kang Bok-gu. Bok-gu is a character who is dynamic in nature and grew up in a foster home. He falls in love with a woman whom he should not love. It was because of the woman, his emotionally-wounded brother fell off from the rooftop and became a human vegetable. So, his love is forbidden and inevitably tragic.