Missing Person (2009)

Won-young is at the center of a dog-eat-dog world where the only thing that matters is where you are in the social hierarchy. Won-young revels in his perverse sexual appetites and beats Gyu-nam who is abandoned by society. But for Gyu-nam, Won-young is the only person who even acknowledges him so he remains, as he himself acknowledges, Won-young's faithful dog.