Charlie is a playboy who's convinced that relationships are dead even though his sister, a therapist, tries to tell him otherwise. His best friends bet him that if he sticks to one woman for one month, he's bound to fall in love. Charlie takes the bet because he believes that he's immune to love. But then he crosses paths with the beautiful and mysterious Eva. Turning on his irresistible charm, Charlie coaxes Eva into a casual affair but soon finds out that Eva has turned the tables on him. Now Charlie is questioning whether he may actually want more than just a one night stand.