Stepfather 3

Gene Clifford escapes from the same institution in Puget Sound he was placed in four years ago. He seeks out a surgeon to alter his appearance. Gene kills the doctor by slitting his throat with a saw and makes his way to Deer View, where he acquires an identity, Keith Grant, as well as a cottage and a job at a nursery. Keith meets principal Christine Davis and her son Andy, who uses a wheelchair after an accident, although doctors believe his continued inability to walk is psychosomatic. Keith and Christine begin dating. A recent boyfriend of Christine who has been monitoring them approaches Keith at his house to warn him off. Keith kills him with a shovel and buries the body in his garden.
Keith and Christine marry, despite Andy's misgivings. Andy's father Steve offers Andy the chance to spend the summer with his family and attend a school for the gifted, and Andy decides to take his father up on the offer, despite Keith's protests. Keith begins courting Jennifer Ashley. Keith plans to murder Christine and marry Jennifer. Keith murders his boss with a rake when Thompson teases him about spotting Keith cheating on Christine with Jennifer. Keith returns home with an axe to kill Christine, but finds that Andy has returned and changes his mind. However, Keith calls Andy "Nicky" which puzzles Christine, though Keith gives her an explanation. Jennifer meets Christine while enrolling Nicky in school; Christine is struck by the name Nicky, coupled with Jennifer mentioning the remote road outside town she and Nicky have rented a house on, which Christine thinks might be Keith's former cottage, which he has sub leased. Keith stops by the school and sees them together and panics. Later, he denies knowing Jennifer.
Andy asks friend Father Ernest Brennan to help him discover Keith's past. Father Brennan agrees, as he knows Andy will try to do it alone if he doesn't. Andy invites Father Brennan to dinner, and sneaks Keith's fork off the table, which he passes to Father Brennan to have the fingerprints analyzed. Keith knows that Father Brennan saw him with Jennifer and Nicky, and has asked him some questions about his past, so he excuses himself after dinner and follows the priest home, running him off the road and making it look like an accident. He also discovers the fork.
Keith rushes to the nursery and calls Jennifer. Jennifer calls Christine to cancel their meeting. Keith reveals he is married before claiming he needs her out of the way. Keith knocks her unconscious and prepares to kill her by feeding her body into a chipper.
Christine and Andy appear. Christine has figured out that Keith is Jennifer's boyfriend and confronts him about the affair. He beats her unconscious when she discovers Jennifer writhing on the ground. Andy finds the courage to get out of his wheelchair and walk. Keith chases him through the nursery until Andy pushes him off the ladder which knocks him into the chipper. Keith is only hanging on the edge and grabs Andy. Christine gets up and helps Andy get away. Jennifer cuts the cable with a hatchet, when the chipper’s engine shuts off. Jennifer sees the pieces of Keith in the chipper. Andy stands up and Christine is surprised and hugs him. Andy turns around and looks at the chipper and says, "Happy Father's Day." They then exit the garden.