Julian (Gosling), an American fugitive from justice, runs a boxing club in Bangkok as a front for his drug business. His mother, the head of a vast criminal organization, arrives from the US to collect the body of her favorite son, Billy. Julian's brother has just been killed after having savagely murdered a young prostitute. Crazy with rage and thirsty for vengeance she demands the heads of the murderers from Julian.
But first, Julian must confront Chang, a mysterious retired policeman - and figurehead of a divine justice - who has resolved to scourge the corrupt underworld of brothels and fight clubs.