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...