Alex Forrest is a charismatic and mysterious woman who enters the life of Dan Gallagher, a successful executive in New York. It all starts as a casual affair during a weekend when his wife, Beth, is out of town. Dan, played by Michael Douglas, is drawn to Alex's intensity, portrayed by Glenn Close, and they both embark on a passionate yet brief relationship. However, what initially seems like a mere fling turns into a nightmare when Dan decides to end the affair and return to his normal life.
Alex, unable to accept rejection, becomes an increasingly threatening presence. Her behavior turns erratic and unpredictable, unleashing a series of disturbing events that not only threaten Dan's marriage but also his very life. From unsettling phone calls to harassment and acts of violence, Alex transforms into an obsessive figure that leads Dan to question his decisions and fight to protect his family.
As the tension rises and the drama intensifies, Dan finds himself caught in a cat-and-mouse game with Alex. The film delves into themes of infidelity, obsession, and the consequences of impulsive decisions. In the end, Dan's struggle to regain control of his life serves as a chilling reminder that some relationships can become dangerous when the boundaries between passion and madness are crossed.