Joo-yeon
Kyung-chul is a dangerous psychopath who kills for pleasure. Soo-hyeon, a top-secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take vengeance against the killer, even if it means that he must become a monster himself.
Several Questions That Make Us Happy is composed of six different stories in a omnibus way, describing mondern society's loneliness, misunderstanding between couples, trust with others, courtesy between lovers, and self-centered blame for others, etc. It is based on the sincere question why we are so unhappy and how I can make happiness.