The film
Joong-ho is a dirty detective turned pimp, who's in financial trouble as several of his girls have recently disappeared without clearing their debts. While trying to track them down, he finds a clue that the vanished girls were all called up by the same client, whom one of his girls is meeting with right now.
Synopsis from TMDB.
The name
Also in The Chaser
Elsewhere on screen, Eom
