Solving a homicide mystery was never an easy task. Bang Yongguk, a young detective had to experience a dreadful first case where one link connected to another, where domino effect existed. Yongguk placed Kwon Jiyong, a drug dealer, as the prime suspect considering he was one building away from where the homicide occurred.  The forensics found a bag filled with drug candies in the victim's pocket. Could it be Jiyong was the murder