The Stepfather is an engrossing suspense thriller that refreshingly doesn’t cheat the audience in terms of valid clues and plot twists.
Terry O’Quinn toplines as a mild-looking guy who immediately is revealed to be a psychotic who has murdered his entire family. A year later he has started a new life as Jerry Blake, married to young Susan (Shelley Hack) who has a teenage daughter Stephanie (Jill Schoelen).
His past eventually catches up with him as his previous brother-in-law Jim (Stephen Shellen) is still researching the murder of his sister with the help of a reporter, the police and (independently) Stephanie’s psychiatrist Dr Bondurant (Charles Lanyer).
What makes The Stepfather work is its believability, as writer Donald Westlake [from a story by him, Carolyn Lefcourt and Brian Garfield] expertly injects clues which can trip up Blake’s new identity. A most ingenious plot peg has Blake carefully planning out his new identity (quitting his job, finding a new home, etc) each time before he goes completely over the edge and sets out to murder his family.
O’Quinn gives a measured, effective performance balancing the normalcy and craziness of the character, while Shoelen is powerfully empathetic as the young heroine. Helmer Joseph Ruben brings a lot more credibility to the film than his previous Dreamscape assignment.