The Stepfather

Grady Edwards kills his wife and three children in the suburban Utah house. He shaves off his beard, dyes his hair, and removes his brown contact lenses to cover his tracks before he exits the home. The crime sets the film's dark premise of a killer living a normal life in plain sight.

Police connect the Utah murder to a similar case in New Jersey, raising fears of a serial killer on the loose. Detectives begin cross-state investigations and note the pattern of household violence. The idea of a roaming killer tensions the community.

Susan Harding, a recently divorced Oregon housewife, meets a man calling himself David Harris in a grocery store and is immediately drawn to him. He fabricates a story about his wife and daughter having died in a car accident, convincing Susan to fall for him. Their engagement is set to be completed in less than six months.

Michael returns from military school and immediately suspects his mother's fiancé. David invites Michael downstairs to the basement, where he offers tequila and tries to win him over. The uneasy dynamic inside the house marks the beginning of escalating danger.

Michael’s suspicions deepen when David uses the wrong name for his supposed deceased daughter. Susan mentions a profile on America's Most Wanted that resembles David, further fueling doubt. The cracks in David's story widen as the trust within the family frays.

David sneaks into the neighbor's house and murders her after Susan recalls warnings about the killer. He uses suffocation and a fall down the basement stairs to carry out the killing. The act demonstrates his willingness to kill to preserve his cover.

David quits his real estate job to avoid showing identification, fueling more suspicion about his past. Jay confronts him about a college history lie, and David responds with violence, clubbing him with a vase and suffocating him. Afterward, he uses Jay's phone to text Michael that everything is okay.

Two weeks pass before the neighbor's body is discovered; David tells the family what happened and Michael overhears a less detailed version from the mailman, which deepens his mistrust. The family struggles with contradictory information and mounting fear. The mystery intensifies as more questions arise.

David intercepts an email from Jackie about hiring an investigator. He tracks her to her house and drowns her in the pool, eliminating another potential threat. His control over the situation grows as the protective circle around Susan tightens.

Michael breaks into the basement to uncover the locked cabinets while Kelly keeps watch. He discovers his father's body in a freezer, shocking him to the core. David knocks out Kelly and traps Michael, escalating the danger inside the family home.

David confronts Susan, belittling her parenting and insisting on control. They struggle, and Susan realizes his true identity, stabbing him in the neck with a shard of a mirror. He collapses in the bathtub, seemingly dead.

Michael escapes the basement and reunites with Kelly while Susan searches for safety. David blocks the stairs and the trio flees to the attic, where Michael and David fight and topple onto the roof, ultimately ending their immediate danger in a fall. Michael wakes later from a coma to learn David is alive and has fled the scene.

The closing scene shows David, now calling himself Chris Ames, at a hardware store and meeting a woman with two young sons, suggesting he has moved on to a new target. The cycle of his disguise continues offscreen as the threat remains.