Choi Hyun-ho

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.

Florist Ae-ran and forensics investigator Min-ho from the Public Prosecutor's Office both have a family that everyone wants. However, Min-ho can't handle bed time so Ae-ran starts a 'challenge game' in which she seduces and has sex with strange men. One day, Ae-ran and Min-ho meet Alex at a tango cafe. Alex is interested in Ae-ran and approaches her while Ae-ran takes interest in Alex who is more handsome than her husband. Min-ho later witnesses them in action and gets angry when he finds out the man Ae-ran seduced is Alex. Min-ho feels nervous because he finds out Alex isn't just a game partner and approached him for a reason. Min-ho tries to get rid of Alex but Alex chokes Ae-ran and Min-ho even more and feels catharsis. The game they started is turning into a catastrophe...