A psychopath's ruthless serial murders have left the entire nation gripped with fear and chaos. A honest and justice-seeking rookie police officer and a veteran detective with tragic past, face against the killer. After the encounter with the psychopath, their lives totally change.

A train ride brings two unlikely souls together as Bae, a committed partner of a serious 10-year relationship, sees her world turned upside down by the charming playboy Kim. Seated together on a business trip from Seoul to Busan, the two find themselves on an adventure to remember.

Nan-ja waves around a shaving knife in a blonde wig, black stockings and miniskirt when the sun goes down. Her aim is to slit the throats of men who have betrayed their women and made them cry. However, her true goal is to take revenge on Gil-soo, Jae-goo and Man-sik who made her mother bite down on bread while they raped her to death. Then one day, Nan-ja finds one of the men she's looking for through a heartbroken woman who was going to kill herself. Nan-ja kidnaps him and drags him to the basement of her hideout where she makes him play the trumpet. Nan-ja dances to the sound of the trumpet until she slits his throat and watch the blood spurt out from the trumpet. Her revenge has begun.

After they lost their parents in a traffic accident, strange events begin to happen to Yeonhui and Yeonsu.

Sung geun, a physical education teacher, is at risk of losing his job when the school decides it needs an English teacher instead of a PE teacher. Therefore, he starts to devise a plan to change his job as an English teacher.

Celebrity guests are split into two teams to compete in various contests. One guest, known only to himself, is designated the "X-Man", and does his best to cause his team to lose the contests. At the end, all guests try to determine the X-Man's identity.

Male and female contestants compete for "each other" in romance games. For example guests have to dance in order to impress the person they are after. Contestants are artists, actors, models, comedians, and MCs of the South Korean entertainment industry.