Tae-seong, a mixed martial arts professional with excellent skills, is injured and got disqualified as he gets caught up in a fight with his friend Byeong-jin inside a store ahead of his UFC debut. Hye-na, Byeong-jin\'s younger sister and BJ professional in mixed martial arts, encourages Tae-seong to make a comeback, but Tae-seong refuses. Hye-na finds out that the man who injured Tae-seong is Yang Ho-yeol, the strongest champion of \"Blood Street\", an illegal gambling game site where one can bet after a real street fighting match, and she informs Tae-seong about it. Tae-seong jumps into \"Blood Street\" for revenge. \"Blood Street\" users go wild, calling masked Tae-seong a \"real fighter\". Tae-seong and Ho-yeol break \"Blood Street\" and start a fight to be the real champion!