After a divorce and escaping her small hometown to live in the big city, Zoey realizes that relationships aren't her thing. While having some drinks with her coworker and best friend, Liam, he again brings up his interest in pushing their friendship to the next level. At first, Zoey disagrees with the prospect of dating until she produces a plan. Under the guise of someone mysterious, Liam can participate in a fun, sexual game with her. The only stipulation is that they must keep their sex life private from their real lives, and Liam must remain in character while playing Codename: Mystery.
Things start out steamy; however, questions form about the character named Mysterious and Liam's actions while in and out of the bedroom. Is Liam as he seems, or is there something darker about the enigmatic figure visiting Zoey at night? Things take a turn for the worse as jealousy makes this innocent game more dangerous than initially planned.