Plot

Ellie tries to mend her marriage with her husband Marcus after a brief encounter with an old friend, David, only to find that David is more dangerous and unstable than she'd realized.

Ellie (Nia Long) tries to mend her marriage with her husband Marcus (Stephen Bishop) after a brief encounter with an old friend, David (Omar Epps), only to find that David is more dangerous and unstable than she'd realized. FATAL AFFAIR is directed by Peter Sullivan.—Netflix

Ellie Warren is a successful attorney living with her husband Marcus who is recovering after a horrible car accident. They have just moved into a new house on the coast from the city of San Francisco now that their daughter Brittany has left for college. Ellie meets her firm's new tech consultant, David Hammond, who both first met each other in college. David is in anger management therapy following an incident with a woman named Deborah. Ellie and David initially meet for drinks, but the situation turns sexual as they go to the bathroom of a club, although Ellie resists. Afterwards, David stalks her via phone calls, texts, viewings of her house from a distance, breaking into her home, hacking into her home security system, sending her a package, and dating Ellie's friend Courtney. This is all despite Ellie's warnings to stay away from her and her family.

Ellie learns from another one of her former college classmates that David murdered his ex-wife Deborah and her new boyfriend a few months after the divorce. Ellie sends Courtney an e-mail with information about Deborah's murder and how David likely committed it, but David deletes it. Ellie is horrified to see him golfing with Marcus. She convinces the concierge at David's building to let her into his apartment, where she finds pictures of Deborah and of herself taken from afar on his computer. As Ellie calls Courtney about the pictures, David gets to Courtney's place and attacks her. She is found bleeding from the head by Ellie and taken to the hospital. With the police now looking for David, he tries to pull a trick on the public by making them think he committed suicide; he sets a homeless man on fire with a suicide note. The police find all the evidence in his home, including a confession for his ex-wife's murder.

One night, Ellie gets a message from her assistant (presumably from David) to sign some documents. Ellie stops by her office and finds her assistant murdered on the floor. Ellie rushes home and calls the police, before she finds David alive and knocks him unconscious with a vase. She encounters the corpse of Brittany's boyfriend Scott, and finds Marcus and Brittany tied up. She frees them as the police arrive, but David kills a cop. As Brittany gets into her car and drives away, a fight ensues between Marcus, David, and Ellie, which ends with David falling to his death on a beach cliff side. A few months later, Marcus and Ellie send Brittany back to school, and their house is for sale.

(copied from Wikipedia)