The Customer Is Always Right

Lee Jang-gil is a barber whose wife work as a insurance agent.through the flash back it is revealed that Lee Jang-gil wife is cheating on him and is having affair with her boss and other colleagues.it seem Lee Jang-gil is having good life but some hidden secret is hiding for which he is very worried. later an old man comes to his shop and begin blackmailing him for the hidden secret which he is hiding.what is the secret? Who is this old man and why is the old man blackmailing?All these are revealed in the end.