The film "The Boy Next Door" is an erotic thriller about casual love with sad consequences.
A pretty literature teacher Claire Peterson is about to become a lady-divorced woman. The break with the unfaithful husband Garrett, who is changing his wife on every business trip, is almost a matter of course. From the last step, the offended spouse is kept only by Kevin's son, tied to his father, and memories of former feelings. Surviving and thinking about the future, Claire gets acquainted with his nephew neighbor - 20-year-old Noah, a friendly, charming and incredibly sexy young man.
Very soon, the attractive handsome becomes Kevin's friend and admirer of his mother. Claire, who needs support, first accepts the help of a young neighbor, and then - his unequivocal courtship. The occasional night of love, which a lonely teacher agrees at an unkind moment, turns into a nightmare. In fact, the courteous Noah turns out to be a real psychopath who considers her neighbor's mistress her property. His insane behavior becomes a threat to the life and mind of the unhappy Claire.