Affair tells the story about a deadly love triangle. Reta and Santi are childhood friends, after not having met for several years they meet again in college. Reta falls in love with Daniel, who Santi has had an affair with. Since Reta has a serious illness, Santi decides to keep her love affair a secret so that Reta's final time will be as good as possible. What Santi doesn't know is that Reta is in fact very much healthy and that she's lying to Santi in order to get Daniel. Let the deadly games of deception begin.