Successful LA marketing analyst Michael Boll (James Spader) seemingly has it all-except a sense of self-confidence. Enigmatic drifter Alex (Rob Lowe) enters Michael's life and immediately begins to exert a negative influence.
As Michael's self-esteem zooms (aided by generous dollops of sex and drugs) he allows himself to be dragooned into a life of crime by the demonic Alex. The doppelganger aspects of Bad Influence, and the film's many unexpected twists and turns, echo films of Alfred Hitchcock, especially Strangers on a Train.
The film's boldest stroke is to cast the likeable Lowe as the bad guy (albeit a charming one) and the often villainous Spader as the malleable milquetoast.