A teenage girl (Jill Schoelen) becomes suspicious of her new stepfather (Terry O'Quinn), believing him to be a serial killer who marries into families, only to murder them when they don't live up to his expectations.
This satisfying horror benefits greatly from a first rate performance from O'Quinn - we know he's the killer because we see him at the start of the film calmly making himself presentable after slaughtering his previous family. He will obsessively invent and sustain a new persona every time something goes awry with his perfect vision of home life. A chilling touch is that we don't know how often he has tried it.
Director Joseph Ruben keeps proceedings largely low-key until the over-the-top ending, and there is some nicely ironic humour in Donald Westlake's script ("Buckle up for safety!"). In its own way, The Stepfather is as subversive about family values as The Texas Chain Saw Massacre, with its single parent family so much safer than one with an abusive husband with unrealistic ideals, especially one as excessively deranged as this. Music by Patrick Moraz. Followed by two sequels, which are nothing special.